diff --git a/.htaccess b/.htaccess
new file mode 100644
index 0000000..f00d481
--- /dev/null
+++ b/.htaccess
@@ -0,0 +1,3 @@
+RewriteEngine on
+RewriteRule ^$ public/ [L]
+RewriteRule (.*) public/$1 [L]
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 3eec3a1..7435db1 100644
--- a/Makefile
+++ b/Makefile
@@ -33,12 +33,7 @@ lint:
 
 .PHONY: api_test
 api_test:
-# If we pass the PFA_API_TEST variable with value 1, we can run the PFA API tests
-ifeq ($(PFA_API_TEST),1)
-	newman run test/postman/scim-opf-pfa.postman_collection.json -e test/postman/scim-env.postman_environment.json
-else
 	newman run test/postman/scim-opf.postman_collection.json -e test/postman/scim-env.postman_environment.json
-endif
 
 .PHONY: unit_test
 unit_test:
diff --git a/README.md b/README.md
index 72cd51d..c7a192f 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,33 @@
 # scim-server-php
 
-**scim-server-php** is a PHP library making it easy to implement [SCIM v2.0](https://datatracker.ietf.org/wg/scim/documents/) server endpoints for various systems.
+This is the Open Provisioning Framework project by audriga which makes use of the [SCIM](http://www.simplecloud.info/) protocol.
+
+---
+
+# Table of Contents
+1. [Info](#info)
+1. [Related projects](#related-projects)
+1. [Capabilities](#capabilities)
+1. [Prerequisites](#prerequisites)
+1. [Usage](#usage)
+    1. [Get it as a composer dependency](#get-it-as-a-composer-dependency)
+    1. [Try out the embedded mock server](#try-out-the-embedded-mock-server)
+        1. [Enable JWT authentication](#enable-jwt-authentication)
+    1. [Use scim-server-php for your own project](#use-scim-server-php-for-your-own-project)
+        1. [SCIM resources](#scim-resources)
+        1. [SCIM server](#scim-server)
+    1. [Authentication/Authorization](#authenticationauthorization)
+        1. [Define your authentication/authorization logic](#define-your-authenticationauthorization-logic)
+        1. [Define your authentication/authorization middleware](#define-your-authenticationauthorization-middleware)
+        1. [Add your authentication/authorization middleware to the SCIM server](#add-your-authenticationauthorization-middleware-to-the-scim-server)
+    1. [Full example](#full-example)
+1. [Acknowledgements](#acknowledgements)
+
+---
+
+## Info
+
+**scim-server-php** is a PHP library which makes it easy to implement [SCIM v2.0](https://datatracker.ietf.org/wg/scim/documents/) server endpoints for various systems.
 
 It is built on the following IETF approved RFCs: [RFC7642](https://datatracker.ietf.org/doc/html/rfc7642), [RFC7643](https://datatracker.ietf.org/doc/html/rfc7643) and [RFC7644](https://datatracker.ietf.org/doc/html/rfc7644)
 
@@ -9,74 +36,146 @@ This is a **work in progress** project. It already works pretty well but some fe
 The **scim-server-php** project currently includes the following:
 
 * A SCIM 2.0 server core library
-* A [Postfix Admin](https://github.com/postfixadmin/postfixadmin) SCIM API
+* An integrated Mock SCIM server based on a SQLite database.
 
-**scim-server-php** also comes with an integrated Mock SCIM server based on a SQLite database.
+## Related projects
 
-## SCIM 2.0 server core library
+* A [Postfix Admin](https://github.com/postfixadmin/postfixadmin) SCIM API based on **scim-server-php** is available at https://github.com/audriga/postfixadmin-scim-api
+* The [Nextcloud SCIM](https://lab.libreho.st/libre.sh/scim/scimserviceprovider) application provides a SCIM API to [NextCloud](https://nextcloud.com/) and uses **scim-server-php** for its SCIM resource models
+
+## Capabilities
 
 This library provides:
 
 * Standard SCIM resources implementations (*Core User*, *Enterprise User* and *Groups*)
 * Custom SCIM resource *Provisioning User* implementation
-* Standard CRUD operation on above SCIM resources
+* Custom SCIM resource *Domain* implementation
+* Standard CRUD operations on above SCIM resources
 * A HTTP server handling requests and responses on defined endpoints, based on the [Slim](https://www.slimframework.com/) framework
-* A very simple JWT implementation
-    * When enabled, a JWT token is generated on the `/jwt` endpoint. You **must** therefore protect this endpoint.
+* A simple JWT implementation
     * When enabled, this JWT token needs to be provided in all requests using the Bearer schema (`Authorization: Bearer <token>`)
+    * You can generate a token with the script located at `bin/generate_jwt.php`
+    * The secret you use *must* be also defined in your `config/config.php` file
 * An easily reusable code architecture for implementing SCIM servers
 
-## Postfix Admin SCIM API
-
-The [Postfix Admin](https://github.com/postfixadmin/postfixadmin) API enables SCIM server capabilities for [Postfix Admin](https://github.com/postfixadmin/postfixadmin). It uses the core library above.
-
-It supports standard GET, POST, PUT and DELETE operations on SCIM *Provisioning User* resources, which are translated in the corresponding operations on the [Postfix Admin](https://github.com/postfixadmin/postfixadmin) mailboxes.
-
-Example (null values removed for readability):
-
-```
-$ curl https://my.postfix.admin.url/Users/aaaa@bli.fr -H 'Authorization: Bearer <token>'
-{
-   "schemas":[
-      "urn:ietf:params:scim:schemas:core:2.0:User",
-      "urn:audriga:params:scim:schemas:extension:provisioning:2.0:User"
-   ],
-   "id":"aaaa@bli.fr",
-   "meta":{
-      "resourceType":"User",
-      "created":"2022-05-27 12:45:08",
-      "location":"https://my.postfix.admin.url/Users/aaaa@bli.fr",
-      "updated":"2022-06-15 13:07:30"
-   },
-   "userName":"aaaa@bli.fr",
-   "name":{
-      "formatted":"Aaaa"
-   },
-   "displayName":"Aaaa",
-   "active":"1",
-   "urn:audriga:params:scim:schemas:extension:provisioning:2.0:User":{
-      "sizeQuota":51200000
-   }
-}
-```
+Note that you can of course use the standard and custom SCIM resources implementations with your own HTTP server if you don't want to use the one provided by **scim-server-php**.
 
 ## Prerequisites
 * **scim-server-php** requires PHP 7.4
 * Dependencies are managed with [composer](https://getcomposer.org/)
 
-## Installation
-### Local installation
-* Run `make install` to automatically install dependencies
+## Usage
 
-### Configuration
-* To switch from the Mock SCIM server to the Postfix Admin SCIM API, you simply need to adapt the `public/index.php` file (include **one** of the following):
+### Get it as a [composer](https://getcomposer.org/) dependency
+
+* You can add the following to your `composer.json` file to get it with [composer](https://getcomposer.org/)
+
+```   
+    "repositories": {
+        "scim": {
+            "type": "vcs",
+            "url": "git@bitbucket.org:audriga/scim-server-php.git"
+        }
+    },
+    "require": {
+        "audriga/scim-server-php": "dev-master"
+    },
+```
+
+* We plan to publish to [packagist](https://packagist.org/) in the future
+
+### Try out the embedded mock server
+
+* To help you use and understand this library, a mock server is provided
+* Clone this repository
+* Run `make install` to automatically install dependencies and setup a mock database
+* Run `make start-server` to start a local mock SCIM server accessible on `localhost:8888`
+* Send your first SCIM requests! For example, try out `curl http://localhost:8888/Users`
+* It supports all basic CRUD operations on SCIM Core Users and Groups
+
+#### Enable JWT authentication
+
+* A very simple JWT authentication is provided
+* Enable it for the embedded mock server by uncommenting the 2 following lines in `public/index.php` and restart it
 
 ```
-// Set up system-specific dependencies
-$dependencies = require dirname(__DIR__) . '/src/Dependencies/mock-dependencies.php'; // include that line if you want to use the integrated mock SCIM server
-$dependencies = require dirname(__DIR__) . '/src/Dependencies/pfa-dependencies.php'; // include that line if you want to use the Postfix Admin SCIM API
+$scimServerPhpAuthMiddleware = 'AuthMiddleware';
+$scimServer->setMiddleware(array($scimServerPhpAuthMiddleware));
 ```
 
+* You will now need to send a valid JWT token with all your requests to the mock server
+    * A JWT token will be considered as valid by the mock server if its secret is identical to the secret set in the `jwt` section of `config/config[.default].php`
+* To generate a token, use the script located at `bin/generate_jwt.php`
+    * Note that this script generates a JWT token including a `user` claim set by the `--user` parameter. You can use any value here in the mock server case.
+
+### Use scim-server-php for your own project
+
+#### SCIM resources
+
+* You can directly reuse the SCIM resources implementation from the `src/Models/SCIM/` folder in any PHP project
+* Here are the provided resources implementations
+    * `src/Models/SCIM/Standard/Users/CoreUser.php` implements the Core User resource from the SCIM standard 
+    * `src/Models/SCIM/Standard/Users/EnterpriseUser.php` implements the Enterprise User extension from the SCIM standard 
+    * `src/Models/SCIM/Standard/Groups/CoreGroup.php` implements the Core Group resource from the SCIM standard 
+    * `src/Models/SCIM/Custom/Domains/Domain.php` implements the custom Domain resource
+    * `src/Models/SCIM/Custom/Users/ProvisioningUser.php` implements the custom Provisioning User extension of the Core User
+
+#### SCIM server
+
+* You can use **scim-server-php** to easily create a full-fledged SCIM server for your own data source
+* **scim-server-php** uses the [Repository Pattern](https://martinfowler.com/eaaCatalog/repository.html) and the [Adapter Pattern](https://en.wikipedia.org/wiki/Adapter_pattern) in order to be as flexible and portable to different systems for provisioning as possible
+* You can use the embedded mock server implementation as an example ;)
+* Concretelly, you will need to implement the following for each resource type of your data source
+    * `Model` classes representing your resources
+        * See e.g. `src/Models/Mock/MockUsers`
+    * `DataAccess` classes defining how to access your data source
+        * See e.g. `src/DataAccess/Users/MockUserDataAccess.php`
+    * `Adapter` classes, extending `AbstractAdapter` and defining how to convert your resources to/from SCIM resources
+        * See e.g. `src/Adapters/Users/MockUserAdapter.php`
+    * `Repository` classes, extending `Opf\Repositories\Repository` and defining the operations available on your resources
+        * See e.g. `src/Repositories/Users/MockUsersRepository.php`
+    * If you want to define new SCIM resources, you will also need to implement new `Controllers` (see `src/Controllers`) and SCIM `Model`s (see `src/Models/SCIM`)
+
+* **scim-server-php** uses [Dependency Injection Container](https://php-di.org/) internally
+    * Create a `dependencies` file reusing the pattern of `src/Dependencies/mock-dependencies.php`
+        * The "Auth middleware" and "Authenticators" sections are explained in the [Authentication/Authorization](#authenticationauthorization) section bellow
+        * Your `Repository` classes will get the corresponding `DataAccess` and `Adapter` classes through the **scim-server-php** container
+
+* Instantiate a `ScimServer` and feed it with your `dependencies` file as shown in `public/index.php`
+    * The "Authentication Middleware" section is explained in the [Authentication/Authorization](#authenticationauthorization) section bellow
+
+### Authentication/Authorization
+
+#### Define your authentication/authorization logic
+
+* Authentication is mostly delegated to the system using **scim-server-php**
+    * A basic JWT based authentication implementation is provided as an example in `src/Util/Authentication/SimpleBearerAuthenticator`
+    * Define your own `Authenticator` class(es) by implementing the `AuthenticatorInterface` available in `Util/Authentication`
+    * A script generating a JWT token containing a single `user` claim is provided in `bin/generate_jwt.php`
+* Authorization is delegated to the system using **scim-server-php**
+
+#### Define your authentication/authorization middleware
+
+* The **scim-server-php** HTTP server is based on the [Slim](https://www.slimframework.com/) framework and reuses its [Middleware](https://www.slimframework.com/docs/v4/concepts/middleware.html) concept
+* Authentication and authorization should therefore be implemented as "Middleware(s)"
+    * This means implementing the `MiddlewareInterface`
+* The authentication middleware should then delegate the actual authentication process to your `Authenticator`
+* The authorization implementation is up to you
+    * You can either integrate it in the `Authenticator` (and so, in the authentication middleware)
+    * Or you can implement an independent authentication middleware
+* You can use `src/Middleware/SimpleAuthMiddleware` as an example
+
+#### Add your authentication/authorization middleware to the SCIM server
+
+* Add your middleware to your dependencies file
+* You can use `src/Dependencies/mock-dependencies.php` as an example
+* Note that the mock `SimpleAuthMiddleware` also uses the **scim-server-php** container to gets the authenticator to use
+    * Hence `src/Dependencies/mock-dependencies.php` defines a `'BearerAuthenticator'` which is then used in `SimpleAuthMiddleware`
+
+### Full example
+
+* We advise to use https://github.com/audriga/postfixadmin-scim-api as a full **scim-server-php** implementation example
+
 ## Acknowledgements
 
 This software is part of the [Open Provisioning Framework](https://www.audriga.com/en/User_provisioning/Open_Provisioning_Framework) project that has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 871498.
\ No newline at end of file
diff --git a/bin/generate_jwt.php b/bin/generate_jwt.php
new file mode 100755
index 0000000..0434270
--- /dev/null
+++ b/bin/generate_jwt.php
@@ -0,0 +1,72 @@
+#!/usr/bin/env php
+<?php
+
+if (file_exists(__DIR__ . '/../vendor/autoload.php')) {
+    require __DIR__ . '/../vendor/autoload.php';
+} else {
+    require __DIR__ . '/../../../../vendor/autoload.php';
+}
+
+use Firebase\JWT\JWT;
+
+/**
+ * A function that prints the usage help message to standard output
+ */
+function showUsage()
+{
+    fwrite(
+        STDOUT,
+        "Usage:
+  generate_jwt.php -u=<username> -s=<secret>
+  generate_jwt.php --username=<username> --secret=<secret>
+  generate_jwt.php (-h | --help)\n"
+    );
+}
+
+/**
+ * Generate a JWT for a given user
+ *
+ * @param string $username The username of the user we generate a JWT for
+ * @param string $secret The JWT secret signing key
+ * @return string The JWT of the user
+ */
+function generateJwt(string $username, string $secret): string
+{
+    $jwtPayload = array(
+        "user" => $username
+    );
+
+    return JWT::encode($jwtPayload, $secret, "HS256");
+}
+
+
+// Specify the CLI options, passed to getopt()
+$shortOptions = "hu:s:";
+$longOptions = ["help", "username:", "secret:"];
+
+// Obtain the CLI args, passed to the script via getopt()
+$cliOptions = getopt($shortOptions, $longOptions);
+
+// If there was some issue with the CLI args, we show the help message
+if ($cliOptions === false) {
+    showUsage();
+    exit(1);
+}
+
+// We check if a username was provided
+if (
+    (isset($cliOptions["u"]) || isset($cliOptions["username"]))
+    && (isset($cliOptions["s"]) || isset($cliOptions["secret"]))    
+) {
+    $username = isset($cliOptions["u"]) ? $cliOptions["u"] : $cliOptions["username"];
+    $secret = isset($cliOptions["s"]) ? $cliOptions["s"] : $cliOptions["secret"];
+} else {
+    // If no username or secret was provided, we let the user know
+    fwrite(STDERR, "A username and a secret JWT key must be provided\n");
+    showUsage();
+    exit(1);
+}
+
+$jwt = generateJwt($username, $secret);
+fwrite(STDOUT, "$jwt\n");
+exit(0);
diff --git a/composer.json b/composer.json
index 13bcca4..9cbcaa3 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
-    "name": "audriga/scim-opf",
-    "description": "An open provisioning framework using the SCIM protocol",
+    "name": "audriga/scim-server-php",
+    "description": "An open library for SCIM servers implementation",
     "type": "library",
     "require": {
         "slim/slim": "^4.10",
@@ -20,8 +20,8 @@
     },
     "authors": [
         {
-            "name": "Stanimir Bozhilov",
-            "email": "stanimir@audriga.com"
+            "name": "audriga",
+            "email": "opensource@audriga.com"
         }
     ],
     "require-dev": {
diff --git a/config/Schema/domainSchema.json b/config/Schema/domainSchema.json
new file mode 100644
index 0000000..5fa618a
--- /dev/null
+++ b/config/Schema/domainSchema.json
@@ -0,0 +1,88 @@
+{
+    "id": "urn:ietf:params:scim:schema:audriga:core:2.0:Domain",
+    "name": "Domain",
+    "description": "Domain",
+    "attributes": [
+        {
+            "name": "domainName",
+            "type": "string",
+            "multiValued": false,
+            "description": "The name of the domain. REQUIRED.",
+            "required": true,
+            "caseExact": false,
+            "mutability": "readWrite",
+            "returned": "default",
+            "uniqueness": "server"
+        },
+        {
+            "name": "description",
+            "type": "string",
+            "multiValued": false,
+            "description": "A description of the domain. OPTIONAL.",
+            "required": false,
+            "caseExact": false,
+            "mutability": "readWrite",
+            "returned": "default",
+            "uniqueness": "none"
+        },
+        {
+            "name": "maxAliases",
+            "type": "int",
+            "multiValued": false,
+            "description": "The maximum number of aliases of the domain. OPTIONAL.",
+            "required": false,
+            "caseExact": false,
+            "mutability": "readWrite",
+            "returned": "default",
+            "uniqueness": "none"
+        },
+        {
+            "name": "maxMailboxes",
+            "type": "int",
+            "multiValued": false,
+            "description": "The maximum number of mailboxes the domain can have. OPTIONAL.",
+            "required": false,
+            "caseExact": false,
+            "mutability": "readWrite",
+            "returned": "default",
+            "uniqueness": "none"
+        },
+        {
+            "name": "maxQuota",
+            "type": "int",
+            "multiValued": false,
+            "description": "The maximum quota, allowed for mailboxes of the domain (in MB). OPTIONAL.",
+            "required": false,
+            "caseExact": false,
+            "mutability": "readWrite",
+            "returned": "default",
+            "uniqueness": "none"
+        },
+        {
+            "name": "usedQuota",
+            "type": "int",
+            "multiValued": false,
+            "description": "The currently used quota by the mailboxes of the domain (in MB). OPTIONAL.",
+            "required": false,
+            "caseExact": false,
+            "mutability": "readOnly",
+            "returned": "default",
+            "uniqueness": "none"
+        },
+        {
+            "name": "active",
+            "type": "bool",
+            "multiValued": false,
+            "description": "A flag indicating whether the domain is currently active. REQUIRED.",
+            "required": true,
+            "caseExact": false,
+            "mutability": "readWrite",
+            "returned": "default",
+            "uniqueness": "none"
+        }
+    ],
+    "meta": {
+        "resourceType": "Schema",
+        "location": "/v2/Schemas/urn:ietf:params:scim:schema:audriga:core:2.0:Domain"
+    }
+}
\ No newline at end of file
diff --git a/config/config.default.php b/config/config.default.php
index 3105797..3d58088 100644
--- a/config/config.default.php
+++ b/config/config.default.php
@@ -2,23 +2,23 @@
 
 return [
     'isInProduction' => false, // Set to true when deploying in production
-    'basePath' => null, // If you want to specify a base path for the Slim app, add it here (e.g., '/test/scim')
+    'basePath' => '', // If you want to specify a base path for the Slim app, add it here (e.g., '/test/scim')
     'supportedResourceTypes' => ['User', 'Group'], // Specify all the supported SCIM ResourceTypes by their names here
 
     // SQLite DB settings
     'db' => [
         'driver' => 'sqlite', // Type of DB
-        'database' => 'db/scim-mock.sqlite' // DB name
+        'databaseFile' => 'db/scim-mock.sqlite' // DB name
     ],
 
-    // PFA MySQL DB settings
+    // MySQL DB settings
     //'db' => [
-    //    'driver' => 'sqlite', // Type of DB
+    //    'driver' => 'mysql', // Type of DB
     //    'host' => 'localhost', // DB host
     //    'port' => '3306', // Port on DB host
-    //    'database' => 'postfix', // DB name
-    //    'user' => 'postfix', // DB user
-    //    'password' => 'postfix123' // DB user's password
+    //    'database' => 'db_name', // DB name
+    //    'user' => 'db_user', // DB user
+    //    'password' => 'db_password' // DB user's password
     //],
 
     // Monolog settings
@@ -30,7 +30,6 @@ return [
 
     // Bearer token settings
     'jwt' => [
-        'secure' => false,
         'secret' => 'secret'
     ]
 ];
diff --git a/public/.htaccess b/public/.htaccess
new file mode 100644
index 0000000..66ef8f6
--- /dev/null
+++ b/public/.htaccess
@@ -0,0 +1,4 @@
+RewriteEngine On
+RewriteCond %{REQUEST_FILENAME} !-f
+RewriteCond %{REQUEST_FILENAME} !-d
+RewriteRule ^ index.php [QSA,L]
diff --git a/public/index.php b/public/index.php
index d5751b2..aa580c1 100644
--- a/public/index.php
+++ b/public/index.php
@@ -1,78 +1,26 @@
 <?php
 
-use DI\ContainerBuilder;
-use Opf\Handlers\HttpErrorHandler;
-use Opf\Util\Util;
-use Slim\Factory\AppFactory;
+use Opf\ScimServer;
 
-require dirname(__DIR__) . '/vendor/autoload.php';
-session_start();
+require __DIR__ . '/../vendor/autoload.php';
 
-// Instantiate the PHP-DI ContainerBuilder
-$containerBuilder = new ContainerBuilder();
+// Obtain the root of the project
+$scimServerPhpRoot = dirname(__DIR__);
 
-$config = Util::getConfigFile();
-if ($config['isInProduction']) {
-    $containerBuilder->enableCompilation(__DIR__ . '/../var/cache');
-}
+// Create a new ScimServer instance and give it the project root
+$scimServer = new ScimServer($scimServerPhpRoot);
 
-// Set up a few Slim-related settings
-$settings = [
-    'settings' => [
-        'determineRouteBeforeAppMiddleware' => false,
-        'displayErrorDetails' => true, // set to false in production
-        'addContentLengthHeader' => false, // Allow the web server to send the content-length header
-    ]
-];
-$containerBuilder->addDefinitions($settings);
+// Take the config file path and pass it to the scimServer instance
+$configFilePath = __DIR__ . '/../config/config.php';
+$scimServer->setConfig($configFilePath);
 
-// Set up common dependencies
-$dependencies = require dirname(__DIR__) . '/src/Dependencies/dependencies.php';
-$dependencies($containerBuilder);
+// Obtain custom dependencies (if any) and pass them to the scimServer instance
+$dependencies = require __DIR__ . '/../src/Dependencies/mock-dependencies.php';
+$scimServer->setDependencies($dependencies);
 
-// Set up system-specific dependencies
-$dependencies = require dirname(__DIR__) . '/src/Dependencies/mock-dependencies.php';
-$dependencies($containerBuilder);
+// Set the Authentication Middleware configured in the dependencies files above to the scimServer instance
+//$scimServerPhpAuthMiddleware = 'AuthMiddleware';
+//$scimServer->setMiddleware(array($scimServerPhpAuthMiddleware));
 
-// Build PHP-DI Container instance
-$container = $containerBuilder->build();
-
-// Instantiate the app
-AppFactory::setContainer($container);
-$app = AppFactory::create();
-$callableResolver = $app->getCallableResolver();
-$responseFactory = $app->getResponseFactory();
-
-// Set our app's base path if it's configured
-if (isset($config['basePath']) && !empty($config['basePath'])) {
-    $app->setBasePath($config['basePath']);
-}
-
-// Set up the ORM
-$eloquent = require dirname(__DIR__) . '/src/eloquent.php';
-$eloquent($app);
-
-// Register routes
-$routes = require dirname(__DIR__) . '/src/routes.php';
-$routes($app);
-
-// Add Routing Middleware
-$app->addRoutingMiddleware();
-$app->addBodyParsingMiddleware();
-
-// Add JWT middleware
-$app->addMiddleware($container->get(JwtAuthentication::class));
-
-// Instantiate our custom Http error handler that we need further down below
-$errorHandler = new HttpErrorHandler($callableResolver, $responseFactory);
-
-// Add error middleware
-$errorMiddleware = $app->addErrorMiddleware(
-    $config['isInProduction'] ? false : true,
-    true,
-    true
-);
-$errorMiddleware->setDefaultErrorHandler($errorHandler);
-
-// Run app
-$app->run();
+// Start the scimServer
+$scimServer->run();
diff --git a/src/Adapters/Groups/MockGroupAdapter.php b/src/Adapters/Groups/MockGroupAdapter.php
index 2a6a0eb..e3c195e 100644
--- a/src/Adapters/Groups/MockGroupAdapter.php
+++ b/src/Adapters/Groups/MockGroupAdapter.php
@@ -3,76 +3,69 @@
 namespace Opf\Adapters\Groups;
 
 use Opf\Adapters\AbstractAdapter;
-use Opf\DataAccess\Groups\MockGroupDataAccess;
+use Opf\Models\Mock\MockGroup;
+use Opf\Models\SCIM\Standard\Groups\CoreGroup;
+use Opf\Models\SCIM\Standard\Meta;
+use Opf\Models\SCIM\Standard\MultiValuedAttribute;
 
 class MockGroupAdapter extends AbstractAdapter
 {
-    /** @var Opf\Models\MockGroup $group */
-    private $group;
-
-    public function getGroup()
+    public function getCoreGroup(?MockGroup $mockGroup): ?CoreGroup
     {
-        return $this->group;
-    }
-
-    public function setGroup(MockGroupDataAccess $group)
-    {
-        $this->group = $group;
-    }
-
-    public function getId()
-    {
-        if (isset($this->group->id) && !empty($this->group->id)) {
-            return $this->group->id;
+        if (!isset($mockGroup)) {
+            return null;
         }
+
+        $coreGroup = new CoreGroup();
+        $coreGroup->setId($mockGroup->getId());
+
+        $coreGroupMeta = new Meta();
+        $coreGroupMeta->setResourceType("Group");
+        $coreGroupMeta->setCreated($mockGroup->getCreatedAt());
+        $coreGroupMeta->setLastModified($mockGroup->getUpdatedAt());
+        $coreGroup->setMeta($coreGroupMeta);
+
+        $coreGroup->setDisplayName($mockGroup->getDisplayName());
+
+        if ($mockGroup->getMembers() !== null && !empty($mockGroup->getMembers())) {
+            $coreGroupMembers = [];
+            foreach ($mockGroup->getMembers() as $mockGroupMember) {
+                $coreGroupMember = new MultiValuedAttribute();
+                $coreGroupMember->setValue($mockGroupMember);
+                $coreGroupMembers[] = $coreGroupMember;
+            }
+
+            $coreGroup->setMembers($coreGroupMembers);
+        }
+
+        return $coreGroup;
     }
 
-    public function setId($id)
+    public function getMockGroup(?CoreGroup $coreGroup): ?MockGroup
     {
-        if (isset($id) && !empty($id)) {
-            $this->group->id = $id;
+        if (!isset($coreGroup)) {
+            return null;
         }
-    }
 
-    public function getCreatedAt()
-    {
-        if (isset($this->group->created_at) && !empty($this->group->created_at)) {
-            return $this->group->created_at;
-        }
-    }
+        $mockGroup = new MockGroup();
+        $mockGroup->setId($coreGroup->getId());
 
-    public function setCreatedAt($createdAt)
-    {
-        if (isset($createdAt) && !empty($createdAt)) {
-            $this->group->created_at = $createdAt;
+        if ($coreGroup->getMeta() !== null) {
+            $mockGroup->setCreatedAt($coreGroup->getMeta()->getCreated());
+            $mockGroup->setUpdatedAt($coreGroup->getMeta()->getLastModified());
         }
-    }
 
-    public function getDisplayName()
-    {
-        if (isset($this->group->displayName) && !empty($this->group->displayName)) {
-            return $this->group->displayName;
-        }
-    }
+        $mockGroup->setDisplayName($coreGroup->getDisplayName());
 
-    public function setDisplayName($displayName)
-    {
-        if (isset($displayName) && !empty($displayName)) {
-            $this->group->displayName = $displayName;
-        }
-    }
+        if ($coreGroup->getMembers() !== null && !empty($coreGroup->getMembers())) {
+            $mockGroupMembers = [];
+            foreach ($coreGroup->getMembers() as $coreGroupMember) {
+                $mockGroupMembers[] = $coreGroupMember->getValue();
+            }
 
-    public function getMembers()
-    {
-        if (isset($this->group->members) && !empty($this->group->members)) {
-            return $this->group->members;
+            $mockGroup->setMembers($mockGroupMembers);
         }
-    }
 
-    public function setMembers($members)
-    {
-        if (isset($members) && !empty($members)) {
-            $this->group->members = $members;
-        }
+        return $mockGroup;
     }
 }
diff --git a/src/Adapters/Users/MockUserAdapter.php b/src/Adapters/Users/MockUserAdapter.php
index a27064c..d09e43f 100644
--- a/src/Adapters/Users/MockUserAdapter.php
+++ b/src/Adapters/Users/MockUserAdapter.php
@@ -3,104 +3,54 @@
 namespace Opf\Adapters\Users;
 
 use Opf\Adapters\AbstractAdapter;
-use Opf\DataAccess\Users\MockUserDataAccess;
+use Opf\Models\Mock\MockUser;
+use Opf\Models\SCIM\Standard\Meta;
+use Opf\Models\SCIM\Standard\Users\CoreUser;
 
 class MockUserAdapter extends AbstractAdapter
 {
-    /** @var Opf\Models\MockUser $user */
-    private $user;
-
-    public function getUser()
+    public function getCoreUser(?MockUser $mockUser): ?CoreUser
     {
-        return $this->user;
-    }
-
-    public function setUser(MockUserDataAccess $user)
-    {
-        $this->user = $user;
-    }
-
-    public function getId()
-    {
-        if (isset($this->user->id) && !empty($this->user->id)) {
-            return $this->user->id;
+        if (!isset($mockUser)) {
+            return null;
         }
+
+        $coreUser = new CoreUser();
+        $coreUser->setId($mockUser->getId());
+        $coreUser->setExternalId($mockUser->getExternalId());
+
+        $coreUserMeta = new Meta();
+        $coreUserMeta->setResourceType("User");
+        $coreUserMeta->setCreated($mockUser->getCreatedAt());
+        $coreUserMeta->setLastModified($mockUser->getUpdatedAt());
+        $coreUser->setMeta($coreUserMeta);
+
+        $coreUser->setUserName($mockUser->getUserName());
+        $coreUser->setActive(boolval($mockUser->getActive()));
+        $coreUser->setProfileUrl($mockUser->getProfileUrl());
+
+        return $coreUser;
     }
 
-    public function setId($id)
+    public function getMockUser(?CoreUser $coreUser): ?MockUser
     {
-        if (isset($id) && !empty($id)) {
-            $this->user->id = $id;
+        if (!isset($coreUser)) {
+            return null;
         }
-    }
 
-    public function getUserName()
-    {
-        if (isset($this->user->userName) && !empty($this->user->userName)) {
-            return $this->user->userName;
-        }
-    }
+        $mockUser = new MockUser();
+        $mockUser->setId($coreUser->getId());
 
-    public function setUserName($userName)
-    {
-        if (isset($userName) && !empty($userName)) {
-            $this->user->userName = $userName;
+        if ($coreUser->getMeta() !== null) {
+            $mockUser->setCreatedAt($coreUser->getMeta()->getCreated());
+            $mockUser->setUpdatedAt($coreUser->getMeta()->getLastModified());
         }
-    }
 
-    public function getCreatedAt()
-    {
-        if (isset($this->user->created_at) && !empty($this->user->created_at)) {
-            return $this->user->created_at;
-        }
-    }
+        $mockUser->setUserName($coreUser->getUserName());
+        $mockUser->setActive(boolval($coreUser->getActive()));
+        $mockUser->setExternalId($coreUser->getExternalId());
+        $mockUser->setProfileUrl($coreUser->getProfileUrl());
 
-    public function setCreatedAt($createdAt)
-    {
-        if (isset($createdAt) && !empty($createdAt)) {
-            $this->user->created_at = $createdAt;
-        }
-    }
-
-    public function getActive()
-    {
-        if (isset($this->user->active) && !empty($this->user->active)) {
-            return boolval($this->user->active);
-        }
-    }
-
-    public function setActive($active)
-    {
-        if (isset($active) && !empty($active)) {
-            $this->user->active = $active;
-        }
-    }
-
-    public function getExternalId()
-    {
-        if (isset($this->user->externalId) && !empty($this->user->externalId)) {
-            return $this->user->externalId;
-        }
-    }
-
-    public function setExternalId($externalId)
-    {
-        if (isset($externalId) && !empty($externalId)) {
-            $this->user->externalId = $externalId;
-        }
-    }
-
-    public function getProfileUrl()
-    {
-        if (isset($this->user->profileUrl) && !empty($this->user->profileUrl)) {
-            return $this->user->profileUrl;
-        }
-    }
-
-    public function setProfileUrl($profileUrl)
-    {
-        if (isset($profileUrl) && !empty($profileUrl)) {
-            $this->user->profileUrl = $profileUrl;
-        }
+        return $mockUser;
     }
 }
diff --git a/src/Adapters/Users/PfaUserAdapter.php b/src/Adapters/Users/PfaUserAdapter.php
deleted file mode 100644
index 15f03ee..0000000
--- a/src/Adapters/Users/PfaUserAdapter.php
+++ /dev/null
@@ -1,100 +0,0 @@
-<?php
-
-namespace Opf\Adapters\Users;
-
-use Exception;
-use Opf\Adapters\AbstractAdapter;
-use Opf\Models\SCIM\Custom\Users\ProvisioningUser;
-use Opf\Models\SCIM\Standard\Meta;
-use Opf\Models\SCIM\Standard\MultiValuedAttribute;
-use Opf\Models\PFA\PfaUser;
-use Opf\Models\SCIM\Standard\Users\Name;
-use Opf\Util\Util;
-
-class PfaUserAdapter extends AbstractAdapter
-{
-    public function getProvisioningUser(?PfaUser $pfaUser): ?ProvisioningUser
-    {
-        if ($pfaUser === null) {
-            return null;
-        }
-        $provisioningUser = new ProvisioningUser();
-        $provisioningUser->setId($pfaUser->getUserName());
-        $provisioningUser->setUserName($pfaUser->getUserName());
-
-        $scimUserMeta = new Meta();
-        $scimUserMeta->setResourceType("User");
-        $scimUserMeta->setCreated($pfaUser->getCreated());
-        $scimUserMeta->setLastModified($pfaUser->getModified());
-        $provisioningUser->setMeta($scimUserMeta);
-
-        $name = new Name();
-        $name->setFormatted($pfaUser->getName());
-        $provisioningUser->setName($name);
-        $provisioningUser->setDisplayName($pfaUser->getName());
-        $provisioningUser->setActive($pfaUser->getActive());
-        $scimUserPhoneNumbers = new MultiValuedAttribute();
-        $scimUserPhoneNumbers->setValue($pfaUser->getPhone());
-        $provisioningUser->setPhoneNumbers(array($scimUserPhoneNumbers));
-
-        $provisioningUser->setSizeQuota($pfaUser->getQuota());
-
-        return $provisioningUser;
-    }
-
-    public function getPfaUser(?ProvisioningUser $provisioningUser): ?PfaUser
-    {
-        if ($provisioningUser === null) {
-            return null;
-        }
-        $pfaUser = new PfaUser();
-
-        if (filter_var($provisioningUser->getUserName(), FILTER_VALIDATE_EMAIL)) {
-            $pfaUser->setUserName($provisioningUser->getUserName());
-        } elseif (filter_var($provisioningUser->getId(), FILTER_VALIDATE_EMAIL)) {
-            $pfaUser->setUserName($provisioningUser->getId());
-        } else {
-            $pfaUser->setUserName($provisioningUser->getEmails()[0]->getValue());
-        }
-        $pfaUser->setPassword($provisioningUser->getPassword());
-        if ($provisioningUser->getName() !== null) {
-            if (!empty($provisioningUser->getName()->getFormatted())) {
-                $pfaUser->setName($provisioningUser->getName()->getFormatted());
-            } else {
-                $formattedName = "";
-                if (!empty($provisioningUser->getName()->getHonorificPrefix())) {
-                    $formattedName = $formattedName . $provisioningUser->getName()->getHonorificPrefix() . " ";
-                }
-                if (!empty($provisioningUser->getName()->getGivenName())) {
-                    $formattedName = $formattedName . $provisioningUser->getName()->getGivenName() . " ";
-                }
-                if (!empty($provisioningUser->getName()->getFamilyName())) {
-                    $formattedName = $formattedName . $provisioningUser->getName()->getFamilyName() . " ";
-                }
-                if (!empty($provisioningUser->getName()->getHonorificSuffix())) {
-                    $formattedName = $formattedName . $provisioningUser->getName()->getHonorificSuffix();
-                }
-                $formattedName = trim($formattedName);
-                if (!empty($formattedName)) {
-                    $pfaUser->setName($formattedName);
-                } else {
-                    $pfaUser->setName($provisioningUser->getDisplayName());
-                }
-            }
-        } else {
-            $pfaUser->setName($provisioningUser->getDisplayName());
-        }
-        $pfaUser->setMaildir(Util::getDomainFromEmail($pfaUser->getUserName()) . "/"
-            . Util::getLocalPartFromEmail($pfaUser->getUserName()) . "/");
-        // We default PFA quota to 0 (unlimited) if not set
-        $pfaUser->setQuota($provisioningUser->getSizeQuota());
-        $pfaUser->setLocalPart(Util::getLocalPartFromEmail($pfaUser->getUserName()));
-        $pfaUser->setDomain(Util::getDomainFromEmail($pfaUser->getUserName()));
-        $pfaUser->setActive($provisioningUser->getActive());
-        if (isset($provisioningUser->getPhoneNumbers()[0])) {
-            $pfaUser->setPhone($provisioningUser->getPhoneNumbers()[0]->getValue());
-        }
-
-        return $pfaUser;
-    }
-}
diff --git a/src/Controllers/Domains/CreateDomainAction.php b/src/Controllers/Domains/CreateDomainAction.php
new file mode 100644
index 0000000..fb507a5
--- /dev/null
+++ b/src/Controllers/Domains/CreateDomainAction.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Opf\Controllers\Domains;
+
+use Exception;
+use Opf\Controllers\Controller;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Slim\Psr7\Response;
+
+final class CreateDomainAction extends Controller
+{
+    public function __construct(ContainerInterface $container)
+    {
+        parent::__construct($container);
+        $this->repository = $this->container->get('DomainsRepository');
+    }
+
+    public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
+    {
+        $this->logger->info("CREATE Domain");
+        $this->logger->info($request->getBody());
+
+        $uri = $request->getUri();
+        $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
+
+        try {
+            $domain = $this->repository->create($request->getParsedBody());
+
+            if (isset($domain) && !empty($domain)) {
+                $this->logger->info("Created domain / domain=" . $domain->getId());
+
+                $scimDomain = $domain->toSCIM(false, $baseUrl);
+
+                $responseBody = json_encode($scimDomain, JSON_UNESCAPED_SLASHES);
+                $this->logger->info($responseBody);
+                $response = new Response($status = 201);
+                $response->getBody()->write($responseBody);
+                $response = $response->withHeader('Content-Type', 'application/scim+json');
+                return $response;
+            } else {
+                $this->logger->error("Error creating domain");
+                $errorResponseBody = json_encode(
+                    ["Errors" => ["description" => "Error creating domain", "code" => 400]]
+                );
+                $response = new Response($status = 400);
+                $response->getBody()->write($errorResponseBody);
+                $response = $response->withHeader('Content-Type', 'application/scim+json');
+                return $response;
+            }
+        } catch (Exception $e) {
+            $this->logger->error("Error creating domain: " . $e->getMessage());
+            $errorResponseBody = json_encode(["Errors" => ["description" => $e->getMessage(), "code" => 400]]);
+            $response = new Response($status = 400);
+            $response->getBody()->write($errorResponseBody);
+            $response = $response->withHeader('Content-Type', 'application/scim+json');
+            return $response;
+        }
+    }
+}
diff --git a/src/Controllers/Domains/DeleteDomainAction.php b/src/Controllers/Domains/DeleteDomainAction.php
new file mode 100644
index 0000000..6ad9afc
--- /dev/null
+++ b/src/Controllers/Domains/DeleteDomainAction.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Opf\Controllers\Domains;
+
+use Opf\Controllers\Controller;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+
+final class DeleteDomainAction extends Controller
+{
+    public function __construct(ContainerInterface $container)
+    {
+        parent::__construct($container);
+        $this->repository = $this->container->get('DomainsRepository');
+    }
+
+    public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
+    {
+        $this->logger->info("DELETE Domain");
+        $id = $request->getAttribute('id');
+        $this->logger->info("ID: " . $id);
+        $deleteRes = $this->repository->delete($id);
+        if (!$deleteRes) {
+            $this->logger->info("Not found");
+            return $response->withStatus(404);
+        }
+        $this->logger->info("Domain deleted");
+
+        $response = $response->withHeader('Content-Type', 'application/scim+json');
+        return $response->withStatus(204);
+    }
+}
diff --git a/src/Controllers/Domains/GetDomainAction.php b/src/Controllers/Domains/GetDomainAction.php
new file mode 100644
index 0000000..ac9f73d
--- /dev/null
+++ b/src/Controllers/Domains/GetDomainAction.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace Opf\Controllers\Domains;
+
+use Opf\Controllers\Controller;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Slim\Psr7\Response;
+
+final class GetDomainAction extends Controller
+{
+    public function __construct(ContainerInterface $container)
+    {
+        parent::__construct($container);
+        $this->repository = $this->container->get('DomainsRepository');
+    }
+
+    public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
+    {
+        $this->logger->info("GET Domain");
+        $uri = $request->getUri();
+        $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
+
+        $id = $request->getAttribute('id');
+        $this->logger->info("ID: " . $id);
+        $domain = $this->repository->getOneById($id);
+        if (!isset($domain) || empty($domain)) {
+            $this->logger->info("Not found");
+            return $response->withStatus(404);
+        }
+
+        $scimDomain = $domain->toSCIM(false, $baseUrl);
+
+        $responseBody = json_encode($scimDomain, JSON_UNESCAPED_SLASHES);
+        $this->logger->info($responseBody);
+        $response = new Response($status = 200);
+        $response->getBody()->write($responseBody);
+        $response = $response->withHeader('Content-Type', 'application/scim+json');
+        return $response;
+    }
+}
diff --git a/src/Controllers/Domains/ListDomainsAction.php b/src/Controllers/Domains/ListDomainsAction.php
new file mode 100644
index 0000000..1bdeb1d
--- /dev/null
+++ b/src/Controllers/Domains/ListDomainsAction.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace Opf\Controllers\Domains;
+
+use Opf\Controllers\Controller;
+use Opf\Models\SCIM\Standard\CoreCollection;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Slim\Psr7\Response;
+
+final class ListDomainsAction extends Controller
+{
+    public function __construct(ContainerInterface $container)
+    {
+        parent::__construct($container);
+        $this->repository = $this->container->get('DomainsRepository');
+    }
+
+    public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
+    {
+        $this->logger->info("GET Domains");
+        $filter = '';
+        if (!empty($request->getQueryParams()['filter'])) {
+            $this->logger->info("Filter --> " . $request->getQueryParams()['filter']);
+            $filter = $request->getQueryParams()['filter'];
+        }
+        $uri = $request->getUri();
+        $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
+
+        $domains = [];
+        $domains = $this->repository->getAll($filter);
+
+        $scimDomains = [];
+        if (!empty($domains)) {
+            foreach ($domains as $domain) {
+                $scimDomains[] = $domain->toSCIM(false, $baseUrl);
+            }
+        }
+        $scimDomainCollection = (new CoreCollection($scimDomains))->toSCIM(false);
+
+        $responseBody = json_encode($scimDomainCollection, JSON_UNESCAPED_SLASHES);
+        $this->logger->info($responseBody);
+        $response = new Response($status = 200);
+        $response->getBody()->write($responseBody);
+        $response = $response->withHeader('Content-Type', 'application/scim+json');
+        return $response;
+    }
+}
diff --git a/src/Controllers/Domains/UpdateDomainAction.php b/src/Controllers/Domains/UpdateDomainAction.php
new file mode 100644
index 0000000..cecc9f0
--- /dev/null
+++ b/src/Controllers/Domains/UpdateDomainAction.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Opf\Controllers\Domains;
+
+use Exception;
+use Opf\Controllers\Controller;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Slim\Psr7\Response;
+
+final class UpdateDomainAction extends Controller
+{
+    public function __construct(ContainerInterface $container)
+    {
+        parent::__construct($container);
+        $this->repository = $this->container->get('DomainsRepository');
+    }
+
+    public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
+    {
+        $this->logger->info("UPDATE Domain");
+        $this->logger->info($request->getBody());
+
+        $uri = $request->getUri();
+        $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
+
+        $id = $request->getAttribute('id');
+        $this->logger->info("ID: " . $id);
+
+        // Try to find a domain with the supplied ID
+        // and if it doesn't exist, return a 404
+        $domain = $this->repository->getOneById($id);
+        if (!isset($domain) || empty($domain)) {
+            $this->logger->info("Not found");
+            return $response->withStatus(404);
+        }
+
+        try {
+            $domain = $this->repository->update($id, $request->getParsedBody());
+            if (isset($domain) && !empty($domain)) {
+                $scimDomain = $domain->toSCIM(false, $baseUrl);
+
+                $responseBody = json_encode($scimDomain, JSON_UNESCAPED_SLASHES);
+                $this->logger->info($responseBody);
+                $response = new Response($status = 200);
+                $response->getBody()->write($responseBody);
+                $response = $response->withHeader('Content-Type', 'application/scim+json');
+                return $response;
+            } else {
+                $this->logger->error("Error updating domain");
+                $errorResponseBody = json_encode(
+                    ["Errors" => ["decription" => "Error updating domain", "code" => 400]]
+                );
+                $response = new Response($status = 400);
+                $response->getBody()->write($errorResponseBody);
+                $response = $response->withHeader('Content-Type', 'application/scim+json');
+                return $response;
+            }
+        } catch (Exception $e) {
+            $this->logger->error("Error updating domain: " . $e->getMessage());
+            $errorResponseBody = json_encode(["Errors" => ["description" => $e->getMessage(), "code" => 400]]);
+            $response = new Response($status = 400);
+            $response->getBody()->write($errorResponseBody);
+            $response = $response->withHeader('Content-Type', 'application/scim+json');
+            return $response;
+        }
+    }
+}
diff --git a/src/Controllers/Groups/ListGroupsAction.php b/src/Controllers/Groups/ListGroupsAction.php
index 03549a6..06e6a3f 100644
--- a/src/Controllers/Groups/ListGroupsAction.php
+++ b/src/Controllers/Groups/ListGroupsAction.php
@@ -20,12 +20,16 @@ final class ListGroupsAction extends Controller
     public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
     {
         $this->logger->info("GET Groups");
-
+        $filter = '';
+        if (!empty($request->getQueryParams()['filter'])) {
+            $this->logger->info("Filter --> " . $request->getQueryParams()['filter']);
+            $filter = $request->getQueryParams()['filter'];
+        }
         $uri = $request->getUri();
         $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
 
         $groups = [];
-        $groups = $this->repository->getAll();
+        $groups = $this->repository->getAll($filter);
 
         $scimGroups = [];
         if (!empty($groups)) {
diff --git a/src/Controllers/JWT/GenerateJWTAction.php b/src/Controllers/JWT/GenerateJWTAction.php
deleted file mode 100644
index 92602fe..0000000
--- a/src/Controllers/JWT/GenerateJWTAction.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-
-namespace Opf\Controllers\JWT;
-
-use Firebase\JWT\JWT;
-use Opf\Controllers\Controller;
-use Opf\Util\Util;
-use Psr\Http\Message\ResponseInterface;
-use Psr\Http\Message\ServerRequestInterface;
-use Slim\Psr7\Response;
-
-class GenerateJWTAction extends Controller
-{
-    public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
-    {
-        // TODO: It'd be good practice to maybe protect this endpoint with basic auth
-        $config = Util::getConfigFile();
-        $settings = $config['jwt'];
-        $token = JWT::encode(["user" => "admin", "password" => "admin"], $settings['secret']);
-
-        $responseBody = json_encode(['Bearer' => $token], JSON_UNESCAPED_SLASHES);
-
-        $response = new Response($status = 200);
-        $response->getBody()->write($responseBody);
-        $response = $response->withHeader('Content-Type', 'application/json');
-        return $response;
-    }
-}
diff --git a/src/Controllers/ServiceProviders/ListResourceTypesAction.php b/src/Controllers/ServiceProviders/ListResourceTypesAction.php
index fb562cd..e5c55a9 100644
--- a/src/Controllers/ServiceProviders/ListResourceTypesAction.php
+++ b/src/Controllers/ServiceProviders/ListResourceTypesAction.php
@@ -21,51 +21,7 @@ final class ListResourceTypesAction extends Controller
         $uri = $request->getUri();
         $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
 
-        // Check which resource types are supported via the config file and in this method further down below
-        // make sure to only return those that are indeed supported
-        $config = Util::getConfigFile();
-        $supportedResourceTypes = $config['supportedResourceTypes'];
-
-        $scimResourceTypes = [];
-
-        if (in_array('User', $supportedResourceTypes)) {
-            $userResourceType = new CoreResourceType();
-            $userResourceType->setId("User");
-            $userResourceType->setName("User");
-            $userResourceType->setEndpoint("/Users");
-            $userResourceType->setDescription("User Account");
-            $userResourceType->setSchema(Util::USER_SCHEMA);
-
-            if (in_array('EnterpriseUser', $supportedResourceTypes)) {
-                $enterpriseUserSchemaExtension = new CoreSchemaExtension();
-                $enterpriseUserSchemaExtension->setSchema(Util::ENTERPRISE_USER_SCHEMA);
-                $enterpriseUserSchemaExtension->setRequired(true);
-
-                $userResourceType->setSchemaExtensions(array($enterpriseUserSchemaExtension));
-            }
-            if (in_array('ProvisioningUser', $supportedResourceTypes)) {
-                $provisioningUserSchemaExtension = new CoreSchemaExtension();
-                $provisioningUserSchemaExtension->setSchema(Util::PROVISIONING_USER_SCHEMA);
-                $provisioningUserSchemaExtension->setRequired(true);
-
-                $userResourceType->setSchemaExtensions(array($provisioningUserSchemaExtension));
-            }
-
-            $scimResourceTypes[] = $userResourceType->toSCIM(false, $baseUrl);
-        }
-
-        if (in_array('Group', $supportedResourceTypes)) {
-            $groupResourceType = new CoreResourceType();
-            $groupResourceType->setId("Group");
-            $groupResourceType->setName("Group");
-            $groupResourceType->setEndpoint("/Groups");
-            $groupResourceType->setDescription("Group");
-            $groupResourceType->setSchema("urn:ietf:params:scim:schemas:core:2.0:Group");
-            $groupResourceType->setSchemaExtensions([]);
-
-            $scimResourceTypes[] = $groupResourceType->toSCIM(false, $baseUrl);
-        }
-
+        $scimResourceTypes = Util::getResourceTypes($baseUrl);
         $scimResourceTypeCollection = (new CoreCollection($scimResourceTypes))->toSCIM(false);
 
         $responseBody = json_encode($scimResourceTypeCollection, JSON_UNESCAPED_SLASHES);
diff --git a/src/Controllers/ServiceProviders/ListSchemasAction.php b/src/Controllers/ServiceProviders/ListSchemasAction.php
index 3de4cb8..1269196 100644
--- a/src/Controllers/ServiceProviders/ListSchemasAction.php
+++ b/src/Controllers/ServiceProviders/ListSchemasAction.php
@@ -15,20 +15,10 @@ final class ListSchemasAction extends Controller
     {
         $this->logger->info("GET Schemas");
 
-        $config = Util::getConfigFile();
-        $supportedSchemas = $config['supportedResourceTypes'];
-        $mandatorySchemas = ['Schema', 'ResourceType'];
+        $scimSchemas = Util::getSchemas();
 
-        $scimSchemas = [];
-
-        // We store the schemas that the SCIM server supports in separate JSON files
-        // That's why we try to read them here and add them to $scimSchemas, which
-        // in turn is then put into the SCIM response body
-        $pathToSchemasDir = dirname(__DIR__, 3) . '/config/Schema';
-        $schemaFiles = scandir($pathToSchemasDir, SCANDIR_SORT_NONE);
-
-        // If scandir() failed (i.e., it returned false), then return 404 (is this spec-compliant?)
-        if ($schemaFiles === false) {
+        // If there were no schemas found, return 404
+        if (is_null($scimSchemas)) {
             $this->logger->info("No Schemas found");
             $response = new Response($status = 404);
             $response = $response->withHeader('Content-Type', 'application/scim+json');
@@ -36,18 +26,6 @@ final class ListSchemasAction extends Controller
             return $response;
         }
 
-        foreach ($schemaFiles as $schemaFile) {
-            if (!in_array($schemaFile, array('.', '..'))) {
-                $scimSchemaJsonDecoded = json_decode(file_get_contents($pathToSchemasDir . '/' . $schemaFile), true);
-
-                // Only return schemas that are either mandatory (like the 'Schema' and 'ResourceType' ones)
-                // or supported by the server
-                if (in_array($scimSchemaJsonDecoded['name'], array_merge($supportedSchemas, $mandatorySchemas))) {
-                    $scimSchemas[] = $scimSchemaJsonDecoded;
-                }
-            }
-        }
-
         $scimSchemasCollection = (new CoreCollection($scimSchemas))->toSCIM(false);
 
         $responseBody = json_encode($scimSchemasCollection, JSON_UNESCAPED_SLASHES);
diff --git a/src/Controllers/ServiceProviders/ListServiceProviderConfigurationsAction.php b/src/Controllers/ServiceProviders/ListServiceProviderConfigurationsAction.php
index 8cb8e2a..a49f54f 100644
--- a/src/Controllers/ServiceProviders/ListServiceProviderConfigurationsAction.php
+++ b/src/Controllers/ServiceProviders/ListServiceProviderConfigurationsAction.php
@@ -3,6 +3,7 @@
 namespace Opf\Controllers\ServiceProviders;
 
 use Opf\Controllers\Controller;
+use Opf\Util\Util;
 use Psr\Http\Message\ResponseInterface;
 use Psr\Http\Message\ServerRequestInterface;
 use Slim\Psr7\Response;
@@ -13,12 +14,9 @@ final class ListServiceProviderConfigurationsAction extends Controller
     {
         $this->logger->info("GET ServiceProviderConfigurations");
 
-        $pathToServiceProviderConfigurationFile =
-            dirname(__DIR__, 3) . '/config/ServiceProviderConfig/serviceProviderConfig.json';
+        $scimServiceProviderConfiguration = Util::getServiceProviderConfig();
 
-        $scimServiceProviderConfigurationFile = file_get_contents($pathToServiceProviderConfigurationFile);
-
-        if ($scimServiceProviderConfigurationFile === false) {
+        if (is_null($scimServiceProviderConfiguration)) {
             $this->logger->info("No ServiceProviderConfiguration found");
             $response = new Response($status = 404);
             $response = $response->withHeader('Content-Type', 'application/scim+json');
@@ -26,7 +24,7 @@ final class ListServiceProviderConfigurationsAction extends Controller
             return $response;
         }
 
-        $responseBody = $scimServiceProviderConfigurationFile;
+        $responseBody = $scimServiceProviderConfiguration;
         $this->logger->info($responseBody);
         $response = new Response($status = 200);
         $response->getBody()->write($responseBody);
diff --git a/src/Controllers/Users/ListUsersAction.php b/src/Controllers/Users/ListUsersAction.php
index f4a6d1e..9dce252 100644
--- a/src/Controllers/Users/ListUsersAction.php
+++ b/src/Controllers/Users/ListUsersAction.php
@@ -21,25 +21,17 @@ final class ListUsersAction extends Controller
     public function __invoke(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
     {
         $this->logger->info("GET Users");
+        $filter = '';
         if (!empty($request->getQueryParams()['filter'])) {
             $this->logger->info("Filter --> " . $request->getQueryParams()['filter']);
+            $filter = $request->getQueryParams()['filter'];
         }
         $uri = $request->getUri();
         $baseUrl = sprintf('%s://%s', $uri->getScheme(), $uri->getAuthority() . $this->basePath);
 
         $userName = null;
         $users = [];
-        if (!empty($request->getQueryParams('filter'))) {
-            $userName = Util::getUserNameFromFilter($request->getQueryParams()['filter']);
-            if (!empty($userName)) {
-                $user = $this->repository->getOneByUserName();
-                if (isset($user) && !empty($user)) {
-                    $users[] = $user;
-                }
-            }
-        } else {
-            $users = $this->repository->getAll();
-        }
+        $users = $this->repository->getAll($filter);
 
         $scimUsers = [];
         if (!empty($users)) {
diff --git a/src/DataAccess/Groups/MockGroupDataAccess.php b/src/DataAccess/Groups/MockGroupDataAccess.php
index 5297390..67d6b3d 100644
--- a/src/DataAccess/Groups/MockGroupDataAccess.php
+++ b/src/DataAccess/Groups/MockGroupDataAccess.php
@@ -2,59 +2,211 @@
 
 namespace Opf\DataAccess\Groups;
 
-use Illuminate\Database\Eloquent\Model;
+use Exception;
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
+use Opf\Models\Mock\MockGroup;
 use Opf\Util\Util;
+use PDO;
+use PDOException;
 
-class MockGroupDataAccess extends Model
+class MockGroupDataAccess
 {
-    protected $table = 'groups';
-    protected $fillable = ['id', 'displayName', 'members', 'created_at'];
-    public $incrementing = false;
+    /** @var PDO */
+    private $dbConnection;
 
-    public $schemas = ["urn:ietf:params:scim:schemas:core:2.0:Group"];
-    private $baseLocation;
+    /** @var \Monolog\Logger */
+    private $logger;
 
-    public function fromArray($data)
+    public function __construct()
     {
-        $this->id = isset($data['id']) ? $data['id'] : (isset($this->id) ? $this->id : Util::genUuid());
-        $this->displayName = $data['displayName'];
-        $this->members = is_string($data['members']) ? $data['members'] : implode(",", $data['members']);
-        $this->created_at = isset($data['created']) ? Util::string2dateTime($data['created']) : new \DateTime('NOW');
+        // Instantiate our logger
+        $this->logger = new Logger(MockGroupDataAccess::class);
+        $this->logger->pushHandler(new StreamHandler(__DIR__ . '/../../../logs/app.log', Logger::DEBUG));
+
+        // Try to obtain a DSN via the Util class and complain with an Exception if there's no DSN
+        $dsn = Util::buildDbDsn();
+        if (!isset($dsn)) {
+            throw new Exception("Can't obtain DSN to connect to DB");
+        }
+
+        // Create the DB connection with PDO (no need to pass username or password for mock DB)
+        $this->dbConnection = new PDO($dsn, null, null);
+
+        // Tell PDO explicitly to throw exceptions on errors, so as to have more info when debugging DB operations
+        $this->dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
     }
 
-    public function fromSCIM($data)
+    public function getAll(): ?array
     {
-        $this->id = isset($data['id']) ? $data['id'] : (isset($this->id) ? $this->id : Util::genUuid());
-        $this->displayName = $data['displayName'];
-        $this->members = is_string($data['members']) ? $data['members'] : implode(",", $data['members']);
-        $this->created_at = isset($data['created']) ? Util::string2dateTime($data['created']) : new \DateTime('NOW');
+        if (isset($this->dbConnection)) {
+            $selectStatement = $this->dbConnection->query("SELECT * from groups");
+            if ($selectStatement) {
+                $mockGroups = [];
+                $mockGroupsRaw = $selectStatement->fetchAll(PDO::FETCH_ASSOC);
+                foreach ($mockGroupsRaw as $group) {
+                    $mockGroup = new MockGroup();
+                    $mockGroup->mapFromArray($group);
+                    $mockGroups[] = $mockGroup;
+                }
+                return $mockGroups;
+            }
+
+            $this->logger->error("Couldn't read all groups from mock DB. SELECT query to DB failed");
+            return null;
+        }
     }
 
-    public function toSCIM($encode = true, $baseLocation = 'http://localhost:8888/v1')
+    public function getOneById($id): ?MockGroup
     {
-        $data = [
-            'schemas' => $this->schemas,
-            'id' => $this->id,
-            'displayName' => $this->displayName,
-            'members' => [],
-            'meta' => [
-                'created' => Util::dateTime2string($this->created_at),
-                'location' => $baseLocation . '/Groups/' . $this->id
-            ]
-        ];
+        if (isset($id) && !empty($id)) {
+            if (isset($this->dbConnection)) {
+                try {
+                    $selectOnePreparedStatement = $this->dbConnection->prepare(
+                        "SELECT * FROM groups WHERE id = ?"
+                    );
 
-        if (!empty($this->members)) {
-            $data['members'] = explode(',', $this->members);
+                    $selectRes = $selectOnePreparedStatement->execute([$id]);
+
+                    if ($selectRes) {
+                        $mockGroupsRaw = $selectOnePreparedStatement->fetchAll(PDO::FETCH_ASSOC);
+                        if ($mockGroupsRaw) {
+                            $mockGroup = new MockGroup();
+                            $mockGroup->mapFromArray($mockGroupsRaw[0]);
+                            return $mockGroup;
+                        } else {
+                            return null;
+                        }
+                    } else {
+                        return null;
+                    }
+                } catch (PDOException $e) {
+                    $this->logger->error($e->getMessage());
+                }
+            }
         }
 
-        if (isset($this->updated_at)) {
-            $data['meta']['updated'] = Util::dateTime2string($this->updated_at);
-        }
+        $this->logger->error(
+            "Argument provided to getOneById in class " . MockGroupDataAccess::class . " is not set or empty"
+        );
+        return null;
+    }
 
-        if ($encode) {
-            $data = json_encode($data);
-        }
+    public function create(MockGroup $groupToCreate): ?MockGroup
+    {
+        $dateNow = date('Y-m-d H:i:s');
 
-        return $data;
+        if (isset($this->dbConnection)) {
+            try {
+                $insertStatement = $this->dbConnection->prepare(
+                    "INSERT INTO groups
+                    (id, displayName, members, created_at, updated_at)
+                    VALUES (?, ?, ?, ?, ?)"
+                );
+
+                $groupToCreate->setId(Util::genUuid());
+
+                $insertRes = $insertStatement->execute([
+                    $groupToCreate->getId(),
+                    $groupToCreate->getDisplayName(),
+                    $groupToCreate->getMembers() !== null && !empty($groupToCreate->getMembers())
+                        ? $groupToCreate->getMembers() : "",
+                    $dateNow,
+                    $dateNow
+                ]);
+
+                if ($insertRes) {
+                    $this->logger->info("Created group " . $groupToCreate->getDisplayName());
+                    return $groupToCreate;
+                } else {
+                    return null;
+                }
+            } catch (PDOException $e) {
+                $this->logger->error($e->getMessage());
+            }
+        } else {
+            $this->logger->error("DB connection not available");
+        }
+        $this->logger->error("Error creating group");
+        return null;
+    }
+
+    public function update(string $id, MockGroup $groupToUpdate): ?MockGroup
+    {
+        $dateNow = date('Y-m-d H:i:s');
+
+        if (isset($this->dbConnection)) {
+            try {
+                $query = "";
+                $values = array();
+
+                if ($groupToUpdate->getDisplayName() !== null) {
+                    $query = $query . "displayName = ?, ";
+                    $values[] = $groupToUpdate->getDisplayName();
+                }
+
+                if ($groupToUpdate->getMembers() !== null) {
+                    $query = $query . "members = ?, ";
+
+                    // We need to transform the string array of user IDs to a single string
+                    $values[] = implode(",", $groupToUpdate->getMembers());
+                }
+
+                if (empty($query)) {
+                    $this->logger->error("No group properties to update");
+                    return null;
+                }
+
+                $query = $query . "updated_at = ? ";
+                $values[] = $dateNow;
+                $values[] = $id;
+
+                $updateStatement = $this->dbConnection->prepare(
+                    "UPDATE groups SET " . $query . " WHERE id = ?"
+                );
+
+                $updateRes = $updateStatement->execute($values);
+
+                if ($updateRes) {
+                    $this->logger->info("Updated group " . $id);
+                    return $this->getOneById($id);
+                } else {
+                    $this->logger->error("Error updating group " . $id);
+                    return null;
+                }
+            } catch (PDOException $e) {
+                $this->logger->error($e->getMessage());
+            }
+        } else {
+            $this->logger->error("Error updating group " . $id . " - DB connection unavailable");
+        }
+        $this->logger->error("Error updating group " . $id);
+        return null;
+    }
+
+    public function delete($id): bool
+    {
+        if (isset($this->dbConnection)) {
+            try {
+                $deleteStatement = $this->dbConnection->prepare(
+                    "DELETE FROM groups WHERE id = ?"
+                );
+                $deleteRes = $deleteStatement->execute([$id]);
+
+                // In case the delete was successful, return true
+                if ($deleteRes) {
+                    $this->logger->info("Deleted group " . $id);
+                    return true;
+                } else {
+                    return false;
+                }
+            } catch (PDOException $e) {
+                $this->logger->error($e->getMessage());
+            }
+        } else {
+            $this->logger->error("Error deleting group " . $id . " - DB connection unavailable");
+        }
+        $this->logger->error("Error deleting group " . $id);
+        return false;
     }
 }
diff --git a/src/DataAccess/Users/MockUserDataAccess.php b/src/DataAccess/Users/MockUserDataAccess.php
index 59b8e0c..321aac0 100644
--- a/src/DataAccess/Users/MockUserDataAccess.php
+++ b/src/DataAccess/Users/MockUserDataAccess.php
@@ -2,67 +2,220 @@
 
 namespace Opf\DataAccess\Users;
 
-use Illuminate\Database\Eloquent\Model;
+use Exception;
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
+use Opf\Models\Mock\MockUser;
 use Opf\Util\Util;
+use PDO;
+use PDOException;
 
-class MockUserDataAccess extends Model
+class MockUserDataAccess
 {
-    protected $table = 'users';
-    protected $fillable = ['id', 'userName', 'created_at', 'active',
-        'externalId', 'profileUrl'];
-    public $incrementing = false;
+    /** @var PDO */
+    private $dbConnection;
 
-    public $schemas = ["urn:ietf:params:scim:schemas:core:2.0:User"];
-    private $baseLocation;
+    /** @var \Monolog\Logger */
+    private $logger;
 
-    public function fromArray($data)
+    public function __construct()
     {
-        $this->id = isset($data['id']) ? $data['id'] : (isset($this->id) ? $this->id : Util::genUuid());
-        $this->userName = isset($data['userName']) ? $data['userName'] : null;
-        $this->created_at = isset($data['created']) ? Util::string2dateTime($data['created'])
-            : (isset($this->created_at) ? $this->created_at : new \DateTime('NOW'));
-        $this->active = isset($data['active']) ? $data['active'] : true;
+        // Instantiate our logger
+        $this->logger = new Logger(MockUserDataAccess::class);
+        $this->logger->pushHandler(new StreamHandler(__DIR__ . '/../../../logs/app.log', Logger::DEBUG));
 
-        $this->externalId = isset($data['externalId']) ? $data['externalId'] : null;
-        $this->profileUrl = isset($data['profileUrl']) ? $data['profileUrl'] : null;
-    }
-
-    public function fromSCIM($data)
-    {
-        $this->id = isset($data['id']) ? $data['id'] : (isset($this->id) ? $this->id : Util::genUuid());
-        $this->userName = isset($data['userName']) ? $data['userName'] : null;
-        $this->created_at = isset($data['meta']) && isset($data['meta']['created'])
-            ? Util::string2dateTime($data['meta']['created'])
-            : (isset($this->created_at) ? $this->created_at : new \DateTime('NOW'));
-        $this->active = isset($data['active']) ? $data['active'] : true;
-
-        $this->externalId = isset($data['externalId']) ? $data['externalId'] : null;
-        $this->profileUrl = isset($data['profileUrl']) ? $data['profileUrl'] : null;
-    }
-
-    public function toSCIM($encode = true, $baseLocation = 'http://localhost:8888/v1')
-    {
-        $data = [
-            'schemas' => $this->schemas,
-            'id' => $this->id,
-            'externalId' => $this->externalId,
-            'meta' => [
-                'created' => Util::dateTime2string($this->created_at),
-                'location' => $baseLocation . '/Users/' . $this->id
-            ],
-            'userName' => $this->userName,
-            'profileUrl' => $this->profileUrl,
-            'active' => (bool) $this->active
-        ];
-
-        if (isset($this->updated_at)) {
-            $data['meta']['updated'] = Util::dateTime2string($this->updated_at);
+        // Try to obtain a DSN via the Util class and complain with an Exception if there's no DSN
+        $dsn = Util::buildDbDsn();
+        if (!isset($dsn)) {
+            throw new Exception("Can't obtain DSN to connect to DB");
         }
 
-        if ($encode) {
-            $data = json_encode($data);
+        // Create the DB connection with PDO (no need to pass username or password for mock DB)
+        $this->dbConnection = new PDO($dsn, null, null);
+
+        // Tell PDO explicitly to throw exceptions on errors, so as to have more info when debugging DB operations
+        $this->dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
+    }
+
+    public function getAll(): ?array
+    {
+        if (isset($this->dbConnection)) {
+            $selectStatement = $this->dbConnection->query("SELECT * from users");
+            if ($selectStatement) {
+                $mockUsers = [];
+                $mockUsersRaw = $selectStatement->fetchAll(PDO::FETCH_ASSOC);
+                foreach ($mockUsersRaw as $user) {
+                    $mockUser = new MockUser();
+                    $mockUser->mapFromArray($user);
+                    $mockUsers[] = $mockUser;
+                }
+                return $mockUsers;
+            }
+
+            $this->logger->error("Couldn't read all users from mock DB. SELECT query to DB failed");
+            return null;
+        }
+    }
+
+    public function getOneById($id): ?MockUser
+    {
+        if (isset($id) && !empty($id)) {
+            if (isset($this->dbConnection)) {
+                try {
+                    $selectOnePreparedStatement = $this->dbConnection->prepare(
+                        "SELECT * FROM users WHERE id = ?"
+                    );
+
+                    $selectRes = $selectOnePreparedStatement->execute([$id]);
+
+                    if ($selectRes) {
+                        $mockUsersRaw = $selectOnePreparedStatement->fetchAll(PDO::FETCH_ASSOC);
+                        if ($mockUsersRaw) {
+                            $mockUser = new MockUser();
+                            $mockUser->mapFromArray($mockUsersRaw[0]);
+                            return $mockUser;
+                        } else {
+                            return null;
+                        }
+                    } else {
+                        return null;
+                    }
+                } catch (PDOException $e) {
+                    $this->logger->error($e->getMessage());
+                }
+            }
         }
 
-        return $data;
+        $this->logger->error(
+            "Argument provided to getOneById in class " . MockUserDataAccess::class . " is not set or empty"
+        );
+        return null;
+    }
+
+    public function create(MockUser $userToCreate): ?MockUser
+    {
+        $dateNow = date('Y-m-d H:i:s');
+
+        if (isset($this->dbConnection)) {
+            try {
+                $insertStatement = $this->dbConnection->prepare(
+                    "INSERT INTO users
+                    (id, userName, active, externalId, profileUrl, created_at, updated_at)
+                    VALUES (?, ?, ?, ?, ?, ?, ?)"
+                );
+
+                $userToCreate->setId(Util::genUuid());
+
+                $insertRes = $insertStatement->execute([
+                    $userToCreate->getId(),
+                    $userToCreate->getUserName(),
+                    $userToCreate->getActive(),
+                    $userToCreate->getExternalId(),
+                    $userToCreate->getProfileUrl(),
+                    $dateNow,
+                    $dateNow
+                ]);
+
+                if ($insertRes) {
+                    $this->logger->info("Created user " . $userToCreate->getUserName());
+                    return $userToCreate;
+                } else {
+                    return null;
+                }
+            } catch (PDOException $e) {
+                $this->logger->error($e->getMessage());
+            }
+        } else {
+            $this->logger->error("DB connection not available");
+        }
+        $this->logger->error("Error creating user");
+        return null;
+    }
+
+    public function update(string $id, MockUser $userToUpdate): ?MockUser
+    {
+        $dateNow = date('Y-m-d H:i:s');
+
+        if (isset($this->dbConnection)) {
+            try {
+                $query = "";
+                $values = array();
+
+                if ($userToUpdate->getUserName() !== null) {
+                    $query = $query . "userName = ?, ";
+                    $values[] = $userToUpdate->getUserName();
+                }
+
+                if ($userToUpdate->getActive() !== null) {
+                    $query = $query . "active = ?, ";
+                    $values[] = $userToUpdate->getActive();
+                }
+
+                if ($userToUpdate->getProfileUrl() !== null) {
+                    $query = $query . "profileUrl = ?, ";
+                    $values[] = $userToUpdate->getProfileUrl();
+                }
+
+                if ($userToUpdate->getExternalId() !== null) {
+                    $query = $query . "externalId = ?, ";
+                    $values[] = $userToUpdate->getExternalId();
+                }
+
+                if (empty($query)) {
+                    $this->logger->error("No user properties to update");
+                    return null;
+                }
+
+                $query = $query . "updated_at = ? ";
+                $values[] = $dateNow;
+                $values[] = $id;
+
+                $updateStatement = $this->dbConnection->prepare(
+                    "UPDATE users SET " . $query . " WHERE id = ?"
+                );
+
+                $updateRes = $updateStatement->execute($values);
+
+                if ($updateRes) {
+                    $this->logger->info("Updated user " . $id);
+                    return $this->getOneById($id);
+                } else {
+                    $this->logger->error("Error updating user " . $id);
+                    return null;
+                }
+            } catch (PDOException $e) {
+                $this->logger->error($e->getMessage());
+            }
+        } else {
+            $this->logger->error("Error updating user " . $id . " - DB connection unavailable");
+        }
+        $this->logger->error("Error updating user " . $id);
+        return null;
+    }
+
+    public function delete($id): bool
+    {
+        if (isset($this->dbConnection)) {
+            try {
+                $deleteStatement = $this->dbConnection->prepare(
+                    "DELETE FROM users WHERE id = ?"
+                );
+                $deleteRes = $deleteStatement->execute([$id]);
+
+                // In case the delete was successful, return true
+                if ($deleteRes) {
+                    $this->logger->info("Deleted user " . $id);
+                    return true;
+                } else {
+                    return false;
+                }
+            } catch (PDOException $e) {
+                $this->logger->error($e->getMessage());
+            }
+        } else {
+            $this->logger->error("Error deleting user " . $id . " - DB connection unavailable");
+        }
+        $this->logger->error("Error deleting user " . $id);
+        return false;
     }
 }
diff --git a/src/DataAccess/Users/PfaUserDataAccess.php b/src/DataAccess/Users/PfaUserDataAccess.php
deleted file mode 100644
index 9992577..0000000
--- a/src/DataAccess/Users/PfaUserDataAccess.php
+++ /dev/null
@@ -1,319 +0,0 @@
-<?php
-
-namespace Opf\DataAccess\Users;
-
-use Exception;
-use Monolog\Handler\StreamHandler;
-use Monolog\Logger;
-use Opf\Util\Util;
-use Opf\Models\PFA\PfaUser;
-use PDO;
-use PDOException;
-
-class PfaUserDataAccess
-{
-    /** @var array */
-    private $config;
-
-    /** @var PDO */
-    private $dbConnection;
-
-    /** @var \Monolog\Logger */
-    private $logger;
-
-    public function __construct()
-    {
-        // Instantiate our logger
-        $this->logger = new Logger(PfaUserDataAccess::class);
-        $this->logger->pushHandler(new StreamHandler(__DIR__ . '/../../../logs/app.log', Logger::DEBUG));
-
-        // Try to obtain a DSN via the Util class and complain with an Exception if there's no DSN
-        $dsn = Util::buildDbDsn();
-        if (!isset($dsn)) {
-            throw new Exception("Can't obtain DSN to connect to DB");
-        }
-
-        $this->config = Util::getConfigFile();
-        if (isset($this->config) && !empty($this->config)) {
-            if (isset($this->config['db']) && !empty($this->config['db'])) {
-                if (
-                    isset($this->config['db']['user'])
-                    && !empty($this->config['db']['user'])
-                    && isset($this->config['db']['password'])
-                    && !empty($this->config['db']['password'])
-                ) {
-                    $dbUsername = $this->config['db']['user'];
-                    $dbPassword = $this->config['db']['password'];
-                } else {
-                    throw new Exception("No DB username and/or password provided to connect to DB");
-                }
-            }
-        }
-
-        // Create the DB connection with PDO
-        $this->dbConnection = new PDO($dsn, $dbUsername, $dbPassword);
-
-        // Tell PDO explicitly to throw exceptions on errors, so as to have more info when debugging DB operations
-        $this->dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
-    }
-
-    public function getAll(): ?array
-    {
-        if (isset($this->dbConnection)) {
-            // TODO: should we use a variable for the table name?
-            // PFA users are 'mailbox' entries (see also https://web.audriga.com/mantis/view.php?id=5806#c28866):
-            // - with a corresponding 'alias' entry
-            // - with the 'alias.address' value being part of the 'alias.goto' value
-            $selectStatement = $this->dbConnection->query("SELECT mailbox.* FROM mailbox INNER JOIN alias 
-                WHERE mailbox.username = alias.address
-                  AND alias.goto LIKE CONCAT('%', alias.address, '%')");
-            if ($selectStatement) {
-                $pfaUsers = [];
-                $pfaUsersRaw = $selectStatement->fetchAll(PDO::FETCH_ASSOC);
-                foreach ($pfaUsersRaw as $user) {
-                    $pfaUser = new PfaUser();
-                    $pfaUser->mapFromArray($user);
-                    $pfaUsers[] = $pfaUser;
-                }
-                return $pfaUsers;
-            }
-
-            $this->logger->error("Couldn't read all users from PFA. SELECT query to DB failed");
-        }
-
-        $this->logger->error("Couldn't connect to DB while attempting to read all users from PFA");
-        return null;
-    }
-
-    // TODO: In the case of PFA, it maybe makes sense to rename this to something like getOneByUsername,
-    // since username is the distinguishing property between users (mailboxes) in PFA and not ID
-    public function getOneById($id): ?PfaUser
-    {
-        if (isset($id) && !empty($id)) {
-            if (isset($this->dbConnection)) {
-                try {
-                    // TODO: should we use a variable for the table name?
-                    $selectOnePreparedStatement = $this->dbConnection->prepare(
-                        "SELECT mailbox.* FROM mailbox INNER JOIN alias
-                            WHERE mailbox.username = alias.address
-                              AND alias.goto LIKE CONCAT('%', alias.address, '%')
-                              AND mailbox.username = ?"
-                    );
-
-                    $selectRes = $selectOnePreparedStatement->execute([$id]);
-
-                    if ($selectRes) {
-                        $pfaUsersRaw = $selectOnePreparedStatement->fetchAll(PDO::FETCH_ASSOC);
-                        if ($pfaUsersRaw) {
-                            $pfaUser = new PfaUser();
-                            $pfaUser->mapFromArray($pfaUsersRaw[0]);
-                            return $pfaUser;
-                        } else {
-                            return null;
-                        }
-                    } else {
-                        return null;
-                    }
-                } catch (PDOException $e) {
-                    $this->logger->error($e->getMessage());
-                }
-            }
-        }
-
-        $this->logger->error(
-            "Argument provided to getOneById in class " . PfaUserDataAccess::class . " is not set or empty"
-        );
-        return null;
-    }
-
-    public function create(PfaUser $userToCreate): ?PfaUser
-    {
-        $dateNow = date('Y-m-d H:i:s');
-        $date2000 = '2000-01-01 00:00:00';
-
-        if (isset($this->dbConnection)) {
-            try {
-                // We want to commit both insert (in mailbox and in alias) in one single commit,
-                // and we want to abort both if something fails
-                $this->dbConnection->beginTransaction();
-
-                // TODO: should we use a variable for the table name?
-                $insertStatement = $this->dbConnection->prepare(
-                    "INSERT INTO mailbox
-                    (username, password, name, maildir, quota, local_part, domain, created, modified, active, phone,
-                     email_other, token, token_validity, password_expiry)
-                    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)"
-                );
-
-                // When performing an INSERT into the mailbox table, maildir, domain and local_part
-                // as columns don't have default values.
-                // That's why here in the prepared statement we currently just give them the value of the empty string,
-                // so as to avoid the issue of MySQL complaining
-                // that nothing is provided for them when they have no default value
-                $insertRes1 = $insertStatement->execute([
-                    $userToCreate->getUserName(),
-                    $userToCreate->getPassword() !== null ? $userToCreate->getPassword() : '',
-                    $userToCreate->getName() !== null ? $userToCreate->getName() : '',
-                    $userToCreate->getMaildir(),
-                    $userToCreate->getQuota() !== null ? $userToCreate->getQuota() : 0,
-                    $userToCreate->getLocalPart(),
-                    $userToCreate->getDomain(),
-                    $dateNow,
-                    $dateNow,
-                    $userToCreate->getActive(),
-                    $userToCreate->getPhone() !== null ? $userToCreate->getPhone() : '',
-                    $userToCreate->getEmailOther() !== null ? $userToCreate->getEmailOther() : '',
-                    $userToCreate->getToken() !== null ? $userToCreate->getToken() : '',
-                    $userToCreate->getTokenValidity() !== null ? $userToCreate->getTokenValidity() : $date2000,
-                    $userToCreate->getPasswordExpiry() !== null ? $userToCreate->getPasswordExpiry() : $date2000
-                ]);
-
-                $insertStatement = $this->dbConnection->prepare(
-                    "INSERT INTO alias
-                    (address, goto, domain, created, modified, active)
-                    VALUES (?, ?, ?, ?, ?, ?)"
-                );
-
-                // When performing an INSERT into the mailbox table, maildir, domain and local_part
-                // as columns don't have default values.
-                // That's why here in the prepared statement we currently just give them the value of the empty string,
-                // so as to avoid the issue of MySQL complaining
-                // that nothing is provided for them when they have no default value
-                $insertRes2 = $insertStatement->execute([
-                    $userToCreate->getUserName(),
-                    $userToCreate->getUserName(),
-                    $userToCreate->getDomain(),
-                    $dateNow,
-                    $dateNow,
-                    $userToCreate->getActive()
-                ]);
-
-                // In case the write was successful, return the user that was just written
-                if ($insertRes1 && $insertRes2) {
-                    $this->dbConnection->commit();
-                    $this->logger->info("Created user " . $userToCreate->getUserName());
-                    return $this->getOneById($userToCreate->getUserName());
-                    //return $userToCreate;
-                } else {
-                    // Otherwise, rollback and just return null
-                    $this->dbConnection->rollBack();
-                    return null;
-                }
-            } catch (PDOException $e) {
-                $this->dbConnection->rollBack();
-                $this->logger->error($e->getMessage());
-            }
-        } else {
-            $this->logger->error("DB connection not available");
-        }
-        $this->logger->error("Error creating user");
-        return null;
-    }
-
-    public function update(string $username, PfaUser $userToUpdate): ?PfaUser
-    {
-        $dateNow = date('Y-m-d H:i:s');
-
-        if (isset($this->dbConnection)) {
-            try {
-                $query = "";
-                $values = array();
-                if ($userToUpdate->getPassword() !== null) {
-                    $query = $query . "password = ?, ";
-                    $values[] = $userToUpdate->getPassword();
-                }
-                if ($userToUpdate->getName() !== null) {
-                    $query = $query . "name = ?, ";
-                    $values[] = $userToUpdate->getName();
-                }
-                if ($userToUpdate->getQuota() !== null) {
-                    $query = $query . "quota = ?, ";
-                    $values[] = $userToUpdate->getQuota();
-                }
-                if ($userToUpdate->getActive() !== null) {
-                    $query = $query . "active = ?, ";
-                    $values[] = $userToUpdate->getActive();
-                }
-                if ($userToUpdate->getEmailOther() !== null) {
-                    $query = $query . "email_other = ?, ";
-                    $values[] = $userToUpdate->getEmailOther();
-                }
-
-                if (empty($query)) {
-                    $this->logger->error("No user properties to update");
-                    return null;
-                }
-
-                $query = $query . "modified = ? ";
-                $values[] = $dateNow;
-                $values[] = $username;
-
-                // Since in PFA the username column in the mailbox table is the primary and is unique,
-                // we use username in this case as an id that serves the purpose of a unique identifier
-                // TODO: should we use a variable for the table name?
-                $updateStatement = $this->dbConnection->prepare(
-                    "UPDATE mailbox SET " . $query . " WHERE username = ?"
-                );
-
-                $updateRes = $updateStatement->execute($values);
-
-                // In case the update was successful, return the user that was just updated
-                if ($updateRes) {
-                    $this->logger->info("Updated user " . $username);
-                    return $this->getOneById($username);
-                } else {
-                    $this->logger->error("Error updating user " . $username);
-                    return null;
-                }
-            } catch (PDOException $e) {
-                $this->logger->error($e->getMessage());
-            }
-        } else {
-            $this->logger->error("Error updating user " . $username . " - DB connection unavailable");
-        }
-        $this->logger->error("Error updating user " . $username);
-        return null;
-    }
-
-    public function delete($username): bool
-    {
-        if (isset($this->dbConnection)) {
-            try {
-                // We want to commit both delete (in mailbox and in alias) in one single commit,
-                // and we want to abort both if something fails
-                $this->dbConnection->beginTransaction();
-
-                // TODO: should we use a variable for the table name?
-                $deleteStatement = $this->dbConnection->prepare(
-                    "DELETE FROM mailbox WHERE username = ?"
-                );
-                $deleteRes1 = $deleteStatement->execute([$username]);
-
-                // TODO: should we use a variable for the table name?
-                $deleteStatement = $this->dbConnection->prepare(
-                    "DELETE FROM alias WHERE address = ?"
-                );
-                $deleteRes2 = $deleteStatement->execute([$username]);
-
-                // In case the delete was successful, return true
-                if ($deleteRes1 && $deleteRes2) {
-                    $this->dbConnection->commit();
-                    $this->logger->info("Deleted user " . $username);
-                    return true;
-                    //return $userToCreate;
-                } else {
-                    // Otherwise, rollback and just return false
-                    $this->dbConnection->rollBack();
-                    return false;
-                }
-            } catch (PDOException $e) {
-                $this->dbConnection->rollBack();
-                $this->logger->error($e->getMessage());
-            }
-        } else {
-            $this->logger->error("Error deleting user " . $username . " - DB connection unavailable");
-        }
-        $this->logger->error("Error deleting user " . $username);
-        return false;
-    }
-}
diff --git a/src/Dependencies/dependencies.php b/src/Dependencies/dependencies.php
index 9d707ae..ddd6427 100644
--- a/src/Dependencies/dependencies.php
+++ b/src/Dependencies/dependencies.php
@@ -2,58 +2,55 @@
 
 declare(strict_types=1);
 
-use DI\ContainerBuilder;
 use Opf\Controllers\Controller;
 use Opf\Util\Util;
 use Psr\Container\ContainerInterface;
 use Psr\Http\Message\ResponseInterface;
 use Tuupola\Middleware\JwtAuthentication;
 
-return function (ContainerBuilder $containerBuilder) {
-    $containerBuilder->addDefinitions([
-        // Monolog
-        Monolog\Logger::class => function (ContainerInterface $c) {
-            $config = Util::getConfigFile();
-            $settings = $config['logger'];
-            $logger = new Monolog\Logger($settings['name']);
-            $logger->pushHandler(new Monolog\Handler\StreamHandler($settings['path'], $settings['level']));
-            return $logger;
-        },
+return [
+    // Monolog
+    Monolog\Logger::class => function () {
+        $config = Util::getConfigFile();
+        $settings = $config['logger'];
+        $logger = new Monolog\Logger($settings['name']);
+        $logger->pushHandler(new Monolog\Handler\StreamHandler($settings['path'], $settings['level']));
+        return $logger;
+    },
 
-        // JWT
-        'JwtAuthentication' => function (ContainerInterface $c) {
-            $config = Util::getConfigFile();
-            $settings = $config['jwt'];
-            $settings["logger"] = $c->get(Monolog\Logger::class);
-            $settings["attribute"] = "jwt";
+    // JWT
+    'JwtAuthentication' => function (ContainerInterface $c) {
+        $config = Util::getConfigFile();
+        $settings = $config['jwt'];
+        $settings["logger"] = $c->get(Monolog\Logger::class);
+        $settings["attribute"] = "jwt";
 
-            // Don't ask for JWT when trying to obtain one
-            $basePath = "";
-            if (isset($config) && !empty($config)) {
-                if (isset($config["basePath"]) && !empty($config["basePath"])) {
-                    $basePath = $config["basePath"];
-                }
+        // Don't ask for JWT when trying to obtain one
+        $basePath = "";
+        if (isset($config) && !empty($config)) {
+            if (isset($config["basePath"]) && !empty($config["basePath"])) {
+                $basePath = $config["basePath"];
             }
-            $settings["ignore"] = [$basePath . "/jwt"];
-
-            if (!isset($settings['error'])) {
-                $settings["error"] = function (
-                    ResponseInterface $response,
-                    $arguments
-                ) {
-                    $data["status"] = "error";
-                    $data["message"] = $arguments["message"];
-                    return $response
-                        ->withHeader("Content-Type", "application/json")
-                        ->getBody()->write(json_encode($data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT));
-                };
-            }
-            return new JwtAuthentication($settings);
-        },
-
-        // Controllers
-        Controller::class => function (ContainerInterface $c) {
-            return new Controller($c);
         }
-    ]);
-};
+        $settings["ignore"] = [$basePath . "/jwt"];
+
+        if (!isset($settings['error'])) {
+            $settings["error"] = function (
+                ResponseInterface $response,
+                $arguments
+            ) {
+                $data["status"] = "error";
+                $data["message"] = $arguments["message"];
+                return $response
+                    ->withHeader("Content-Type", "application/json")
+                    ->getBody()->write(json_encode($data, JSON_UNESCAPED_SLASHES | JSON_PRETTY_PRINT));
+            };
+        }
+        return new JwtAuthentication($settings);
+    },
+
+    // Controllers
+    Controller::class => function (ContainerInterface $c) {
+        return new Controller($c);
+    }
+];
diff --git a/src/Dependencies/mock-dependencies.php b/src/Dependencies/mock-dependencies.php
index 395f8d3..807fc69 100644
--- a/src/Dependencies/mock-dependencies.php
+++ b/src/Dependencies/mock-dependencies.php
@@ -2,45 +2,51 @@
 
 declare(strict_types=1);
 
-use DI\ContainerBuilder;
 use Opf\Adapters\Groups\MockGroupAdapter;
 use Opf\Adapters\Users\MockUserAdapter;
-use Opf\Controllers\Controller;
 use Opf\DataAccess\Groups\MockGroupDataAccess;
 use Opf\DataAccess\Users\MockUserDataAccess;
+use Opf\Middleware\SimpleAuthMiddleware;
 use Opf\Repositories\Groups\MockGroupsRepository;
 use Opf\Repositories\Users\MockUsersRepository;
+use Opf\Util\Authentication\SimpleBearerAuthenticator;
 use Psr\Container\ContainerInterface;
-use Psr\Http\Message\ResponseInterface;
-use Tuupola\Middleware\JwtAuthentication;
 
-return function (ContainerBuilder $containerBuilder) {
-    $containerBuilder->addDefinitions([
-        // Repositories
-        'UsersRepository' => function (ContainerInterface $c) {
-            return new MockUsersRepository($c);
-        },
+return [
+    // Repositories
+    'UsersRepository' => function (ContainerInterface $c) {
+        return new MockUsersRepository($c);
+    },
 
-        'GroupsRepository' => function (ContainerInterface $c) {
-            return new MockGroupsRepository($c);
-        },
+    'GroupsRepository' => function (ContainerInterface $c) {
+        return new MockGroupsRepository($c);
+    },
 
-        // Data access classes
-        'UsersDataAccess' => function () {
-            return new MockUserDataAccess();
-        },
+    // Data access classes
+    'UsersDataAccess' => function () {
+        return new MockUserDataAccess();
+    },
 
-        'GroupsDataAccess' => function () {
-            return new MockGroupDataAccess();
-        },
+    'GroupsDataAccess' => function () {
+        return new MockGroupDataAccess();
+    },
 
-        // Adapters
-        'UsersAdapter' => function () {
-            return new MockUserAdapter();
-        },
+    // Adapters
+    'UsersAdapter' => function () {
+        return new MockUserAdapter();
+    },
 
-        'GroupsAdapter' => function () {
-            return new MockGroupAdapter();
-        }
-    ]);
-};
+    'GroupsAdapter' => function () {
+        return new MockGroupAdapter();
+    },
+
+    // Auth middleware
+    'AuthMiddleware' => function (ContainerInterface $c) {
+        return new SimpleAuthMiddleware($c);
+    },
+
+    // Authenticators (used by SimpleAuthMiddleware)
+    'BearerAuthenticator' => function (ContainerInterface $c) {
+        return new SimpleBearerAuthenticator($c);
+    }
+];
diff --git a/src/Dependencies/pfa-dependencies.php b/src/Dependencies/pfa-dependencies.php
deleted file mode 100644
index c7279ca..0000000
--- a/src/Dependencies/pfa-dependencies.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-use DI\ContainerBuilder;
-use Opf\Adapters\Users\PfaUserAdapter;
-use Opf\DataAccess\Users\PfaUserDataAccess;
-use Opf\Repositories\Users\PfaUsersRepository;
-use Psr\Container\ContainerInterface;
-
-return function (ContainerBuilder $containerBuilder) {
-    $containerBuilder->addDefinitions([
-        // Repositories
-        'UsersRepository' => function (ContainerInterface $c) {
-            return new PfaUsersRepository($c);
-        },
-
-        // Data access classes
-        'UsersDataAccess' => function () {
-            return new PfaUserDataAccess();
-        },
-
-        // Adapters
-        'UsersAdapter' => function () {
-            return new PfaUserAdapter();
-        }
-    ]);
-};
diff --git a/src/Handlers/HttpErrorHandler.php b/src/Handlers/HttpErrorHandler.php
index 39a3c4b..bd5d536 100644
--- a/src/Handlers/HttpErrorHandler.php
+++ b/src/Handlers/HttpErrorHandler.php
@@ -69,6 +69,7 @@ class HttpErrorHandler extends ErrorHandler
         $payload = json_encode($error, JSON_PRETTY_PRINT);
 
         $response = $this->responseFactory->createResponse($statusCode);
+        $response = $response->withHeader('Content-Type', 'application/scim+json');
         $response->getBody()->write($payload);
 
         return $response;
diff --git a/src/Middleware/SimpleAuthMiddleware.php b/src/Middleware/SimpleAuthMiddleware.php
new file mode 100644
index 0000000..e0e1173
--- /dev/null
+++ b/src/Middleware/SimpleAuthMiddleware.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Opf\Middleware;
+
+use Opf\Util\Authentication\SimpleBearerAuthenticator;
+use Psr\Container\ContainerInterface;
+use Psr\Http\Message\ServerRequestInterface as Request;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface as RequestHandler;
+use Slim\Psr7\Response;
+use Slim\Routing\RouteContext;
+
+class SimpleAuthMiddleware implements MiddlewareInterface
+{
+    /** @var \Opf\Util\Authentication\SimpleBearerAuthenticator */
+    private $bearerAuthenticator;
+
+    public function __construct(ContainerInterface $container)
+    {
+        $this->bearerAuthenticator = $container->get('BearerAuthenticator');
+    }
+
+    public function process(Request $request, RequestHandler $handler): Response
+    {
+        // If no 'Authorization' header supplied, we directly return a 401
+        if (!$request->hasHeader('Authorization')) {
+            return new Response(401);
+        }
+
+        // $request->getHeader() gives back a string array, hence the need for [0]
+        $authHeader = $request->getHeader('Authorization')[0];
+
+        // Obtain the auth type and the supplied credentials
+        $authHeaderSplit = explode(' ', $authHeader);
+        $authType = $authHeaderSplit[0];
+        $authCredentials = $authHeaderSplit[1];
+
+        // This is a flag that tracks whether auth succeeded or not
+        $isAuthSuccessful = false;
+
+        $authorizationInfo = [];
+
+        // Call the right authenticator, based on the auth type
+        if (strcmp($authType, 'Bearer') === 0) {
+            $isAuthSuccessful = $this->bearerAuthenticator->authenticate($authCredentials, $authorizationInfo);
+        }
+
+        // If everything went fine, let the request pass through
+        if ($isAuthSuccessful) {
+            return $handler->handle($request);
+        }
+
+        // If something didn't go right so far, then return a 401
+        return new Response(401);
+    }
+}
diff --git a/src/Models/Mock/MockCommonEntity.php b/src/Models/Mock/MockCommonEntity.php
new file mode 100644
index 0000000..216e78b
--- /dev/null
+++ b/src/Models/Mock/MockCommonEntity.php
@@ -0,0 +1,45 @@
+<?php
+
+namespace Opf\Models\Mock;
+
+class MockCommonEntity
+{
+    /** @var string|null $id */
+    protected $id;
+
+    /** @var string|null $createdAt */
+    protected $createdAt;
+
+    /** @var string|null $updatedAt */
+    protected $updatedAt;
+
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    public function setId($id)
+    {
+        $this->id = $id;
+    }
+
+    public function getCreatedAt()
+    {
+        return $this->createdAt;
+    }
+
+    public function setCreatedAt($createdAt)
+    {
+        $this->createdAt = $createdAt;
+    }
+
+    public function getUpdatedAt()
+    {
+        return $this->updatedAt;
+    }
+
+    public function setUpdatedAt($updatedAt)
+    {
+        $this->updatedAt = $updatedAt;
+    }
+}
diff --git a/src/Models/Mock/MockGroup.php b/src/Models/Mock/MockGroup.php
new file mode 100644
index 0000000..5e5c6ec
--- /dev/null
+++ b/src/Models/Mock/MockGroup.php
@@ -0,0 +1,69 @@
+<?php
+
+namespace Opf\Models\Mock;
+
+class MockGroup extends MockCommonEntity
+{
+    /** @var string|null $displayName */
+    private $displayName;
+
+    /** @var array<string>|null $members */
+    private $members;
+
+    public function mapFromArray($properties = null): bool
+    {
+        $result = true;
+        if ($properties !== null) {
+            foreach ($properties as $key => $value) {
+                if (strcasecmp($key, 'id') === 0) {
+                    $this->id = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'created_at') === 0) {
+                    $this->createdAt = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'updated_at') === 0) {
+                    $this->updatedAt = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'displayName') === 0) {
+                    $this->displayName = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'members') === 0) {
+                    $this->members = $value;
+                    continue;
+                }
+                $result = false;
+            }
+        } else {
+            $result = false;
+        }
+        return $result;
+    }
+
+    public function getDisplayName()
+    {
+        return $this->displayName;
+    }
+
+    public function setDisplayName($displayName)
+    {
+        $this->displayName = $displayName;
+    }
+
+    public function getMembers()
+    {
+        return $this->members;
+    }
+
+    public function setMembers($members)
+    {
+        $this->members = $members;
+    }
+}
diff --git a/src/Models/Mock/MockUser.php b/src/Models/Mock/MockUser.php
new file mode 100644
index 0000000..8b82477
--- /dev/null
+++ b/src/Models/Mock/MockUser.php
@@ -0,0 +1,111 @@
+<?php
+
+namespace Opf\Models\Mock;
+
+class MockUser extends MockCommonEntity
+{
+    /** @var string|null $userName */
+    private $userName;
+
+    /** @var bool $active */
+    private $active;
+
+    /** @var string|null $externalId */
+    private $externalId;
+
+    /** @var string|null $profileUrl */
+    private $profileUrl;
+
+    public function mapFromArray($properties = null): bool
+    {
+        $result = true;
+        if ($properties !== null) {
+            foreach ($properties as $key => $value) {
+                if (strcasecmp($key, 'id') === 0) {
+                    $this->id = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'created_at') === 0) {
+                    $this->createdAt = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'updated_at') === 0) {
+                    $this->updatedAt = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'userName') === 0) {
+                    $this->userName = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'active') === 0) {
+                    if ($value === "1") {
+                        $this->active = true;
+                    } elseif ($value === "0") {
+                        $this->active = false;
+                    } else {
+                        $this->active = $value;
+                    }
+                    continue;
+                }
+
+                if (strcasecmp($key, 'externalId') === 0) {
+                    $this->externalId = $value;
+                    continue;
+                }
+
+                if (strcasecmp($key, 'profileUrl') === 0) {
+                    $this->profileUrl = $value;
+                    continue;
+                }
+                $result = false;
+            }
+        } else {
+            $result = false;
+        }
+        return $result;
+    }
+
+    public function getUserName()
+    {
+        return $this->userName;
+    }
+
+    public function setUserName($userName)
+    {
+        $this->userName = $userName;
+    }
+
+    public function getActive()
+    {
+        return $this->active;
+    }
+
+    public function setActive($active)
+    {
+        $this->active = $active;
+    }
+
+    public function getExternalId()
+    {
+        return $this->externalId;
+    }
+
+    public function setExternalId($externalId)
+    {
+        $this->externalId = $externalId;
+    }
+
+    public function getProfileUrl()
+    {
+        return $this->profileUrl;
+    }
+
+    public function setProfileUrl($profileUrl)
+    {
+        $this->profileUrl = $profileUrl;
+    }
+}
diff --git a/src/Models/PFA/PfaUser.php b/src/Models/PFA/PfaUser.php
deleted file mode 100644
index 6348ff0..0000000
--- a/src/Models/PFA/PfaUser.php
+++ /dev/null
@@ -1,364 +0,0 @@
-<?php
-
-namespace Opf\Models\PFA;
-
-class PfaUser
-{
-    /** @var string|null $userName */
-    private ?string $userName = null;
-
-    /** @var string|null $password */
-    private ?string $password = null;
-
-    /** @var string|null $name */
-    private ?string $name = null;
-
-    /** @var string|null $maildir */
-    private ?string $maildir = null;
-
-    /** @var int|null $quota */
-    private ?int $quota = null;
-
-    /** @var string|null $localPart */
-    private ?string $localPart = null;
-
-    /** @var string|null $domain */
-    private ?string $domain = null;
-
-    /** @var string|null $created */
-    private ?string $created = null;
-
-    /** @var string|null $modified */
-    private ?string $modified = null;
-
-    /** @var string|null $active */
-    private ?string $active = null;
-
-    /** @var string|null $phone */
-    private ?string $phone = null;
-
-    /** @var string|null $emailOther */
-    private ?string $emailOther = null;
-
-    /** @var string|null $token */
-    private ?string $token = null;
-
-    /** @var string|null $tokenValidity */
-    private ?string $tokenValidity = null;
-
-    /** @var string|null $passwordExpiry */
-    private ?string $passwordExpiry = null;
-
-    public function mapFromArray($properties = null): bool
-    {
-        $result = true;
-        if ($properties !== null) {
-            foreach ($properties as $key => $value) {
-                if (strcasecmp($key, 'userName') === 0) {
-                    $this->userName = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'password') === 0) {
-                    $this->password = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'name') === 0) {
-                    $this->name = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'maildir') === 0) {
-                    $this->maildir = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'quota') === 0) {
-                    $this->quota = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'localpart') === 0) {
-                    $this->localpart = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'domain') === 0) {
-                    $this->domain = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'created') === 0) {
-                    $this->created = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'modified') === 0) {
-                    $this->modified = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'active') === 0) {
-                    $this->active = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'phone') === 0) {
-                    $this->phone = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'emailOther') === 0) {
-                    $this->emailOther = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'token') === 0) {
-                    $this->token = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'tokenValidity') === 0) {
-                    $this->tokenValidity = $value;
-                    continue;
-                }
-                if (strcasecmp($key, 'passwordExpiry') === 0) {
-                    $this->passwordExpiry = $value;
-                    continue;
-                }
-                $result = false;
-            }
-        } else {
-            $result = false;
-        }
-        return $result;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getUserName(): ?string
-    {
-        return $this->userName;
-    }
-
-    /**
-     * @param string|null $userName
-     */
-    public function setUserName(?string $userName): void
-    {
-        $this->userName = $userName;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getPassword(): ?string
-    {
-        return $this->password;
-    }
-
-    /**
-     * @param string|null $password
-     */
-    public function setPassword(?string $password): void
-    {
-        $this->password = $password;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getName(): ?string
-    {
-        return $this->name;
-    }
-
-    /**
-     * @param string|null $name
-     */
-    public function setName(?string $name): void
-    {
-        $this->name = $name;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getMaildir(): ?string
-    {
-        return $this->maildir;
-    }
-
-    /**
-     * @param string|null $maildir
-     */
-    public function setMaildir(?string $maildir): void
-    {
-        $this->maildir = $maildir;
-    }
-
-    /**
-     * @return int|null
-     */
-    public function getQuota(): ?int
-    {
-        return $this->quota;
-    }
-
-    /**
-     * @param int|null $quota
-     */
-    public function setQuota(?int $quota): void
-    {
-        $this->quota = $quota;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getLocalPart(): ?string
-    {
-        return $this->localPart;
-    }
-
-    /**
-     * @param string|null $localPart
-     */
-    public function setLocalPart(?string $localPart): void
-    {
-        $this->localPart = $localPart;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getDomain(): ?string
-    {
-        return $this->domain;
-    }
-
-    /**
-     * @param string|null $domain
-     */
-    public function setDomain(?string $domain): void
-    {
-        $this->domain = $domain;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getCreated(): ?string
-    {
-        return $this->created;
-    }
-
-    /**
-     * @param string|null $created
-     */
-    public function setCreated(?string $created): void
-    {
-        $this->created = $created;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getModified(): ?string
-    {
-        return $this->modified;
-    }
-
-    /**
-     * @param string|null $modified
-     */
-    public function setModified(?string $modified): void
-    {
-        $this->modified = $modified;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getActive(): ?string
-    {
-        return $this->active;
-    }
-
-    /**
-     * @param string|null $active
-     */
-    public function setActive(?string $active): void
-    {
-        $this->active = $active;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getPhone(): ?string
-    {
-        return $this->phone;
-    }
-
-    /**
-     * @param string|null $phone
-     */
-    public function setPhone(?string $phone): void
-    {
-        $this->phone = $phone;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getEmailOther(): ?string
-    {
-        return $this->emailOther;
-    }
-
-    /**
-     * @param string|null $emailOther
-     */
-    public function setEmailOther(?string $emailOther): void
-    {
-        $this->emailOther = $emailOther;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getToken(): ?string
-    {
-        return $this->token;
-    }
-
-    /**
-     * @param string|null $token
-     */
-    public function setToken(?string $token): void
-    {
-        $this->token = $token;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getTokenValidity(): ?string
-    {
-        return $this->tokenValidity;
-    }
-
-    /**
-     * @param string|null $tokenValidity
-     */
-    public function setTokenValidity(?string $tokenValidity): void
-    {
-        $this->tokenValidity = $tokenValidity;
-    }
-
-    /**
-     * @return string|null
-     */
-    public function getPasswordExpiry(): ?string
-    {
-        return $this->passwordExpiry;
-    }
-
-    /**
-     * @param string|null $passwordExpiry
-     */
-    public function setPasswordExpiry(?string $passwordExpiry): void
-    {
-        $this->passwordExpiry = $passwordExpiry;
-    }
-}
diff --git a/src/Models/SCIM/Custom/Domains/Domain.php b/src/Models/SCIM/Custom/Domains/Domain.php
index 7e92662..e3a4445 100644
--- a/src/Models/SCIM/Custom/Domains/Domain.php
+++ b/src/Models/SCIM/Custom/Domains/Domain.php
@@ -2,7 +2,221 @@
 
 namespace Opf\Models\SCIM\Custom\Domains;
 
-// TODO: This is currently a dummy class to demonstrate how to add custom SCIM resources to the codebase
-class Domain
+use Opf\Models\SCIM\Standard\CommonEntity;
+use Opf\Models\SCIM\Standard\Meta;
+use Opf\Util\Util;
+
+class Domain extends CommonEntity
 {
+    /** @var string|null $domainName */
+    private ?string $domainName;
+
+    /** @var string|null $description */
+    private ?string $description = null;
+
+    /** @var int $maxAliases */
+    private int $maxAliases;
+
+    /** @var int $maxMailboxes */
+    private int $maxMailboxes;
+
+    /** @var int $maxQuota */
+    private int $maxQuota;
+
+    /** @var int $usedQuota */
+    private int $usedQuota;
+
+    /** @var bool $active */
+    private bool $active;
+
+    /**
+     * @return string|null
+     */
+    public function getDomainName(): ?string
+    {
+        return $this->domainName;
+    }
+
+    /**
+     * @param string|null $domainName
+     */
+    public function setDomainName(?string $domainName): void
+    {
+        $this->domainName = $domainName;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getDescription(): ?string
+    {
+        return $this->description;
+    }
+
+    /**
+     * @param string|null $description
+     */
+    public function setDescription(?string $description): void
+    {
+        $this->description = $description;
+    }
+
+    /**
+     * @return int
+     */
+    public function getMaxAliases(): int
+    {
+        return $this->maxAliases;
+    }
+
+    /**
+     * @param int $maxAliases
+     */
+    public function setMaxAliases(int $maxAliases): void
+    {
+        $this->maxAliases = $maxAliases;
+    }
+
+    /**
+     * @return int
+     */
+    public function getMaxMailboxes(): int
+    {
+        return $this->maxMailboxes;
+    }
+
+    /**
+     * @param int $maxMailboxes
+     */
+    public function setMaxMailboxes(int $maxMailboxes): void
+    {
+        $this->maxMailboxes = $maxMailboxes;
+    }
+
+    /**
+     * @return int
+     */
+    public function getMaxQuota(): int
+    {
+        return $this->maxQuota;
+    }
+
+    /**
+     * @param int $maxQuota
+     */
+    public function setMaxQuota(int $maxQuota): void
+    {
+        $this->maxQuota = $maxQuota;
+    }
+
+    /**
+     * @return int
+     */
+    public function getUsedQuota(): int
+    {
+        return $this->usedQuota;
+    }
+
+    /**
+     * @param int $usedQuota
+     */
+    public function setUsedQuota(int $usedQuota): void
+    {
+        $this->usedQuota = $usedQuota;
+    }
+
+    /**
+     * @return bool
+     */
+    public function getActive(): bool
+    {
+        return $this->active;
+    }
+
+    /**
+     * @param bool $active
+     */
+    public function setActive(bool $active): void
+    {
+        $this->active = $active;
+    }
+
+    /**
+     * Create a Domain object from JSON SCIM data
+     *
+     * @param array $data The JSON SCIM data
+     */
+    public function fromSCIM(array $data)
+    {
+        if (isset($data['id'])) {
+            $this->setId($data['id']);
+        }
+
+        $this->setExternalId(isset($data['externalId']) ? $data['externalId'] : null);
+
+        $this->setDomainName(isset($data['domainName']) ? $data['domainName'] : null);
+        $this->setDescription(isset($data['description']) ? $data['description'] : null);
+
+        // For the int attributes that are set below, we set 0 as the default value
+        // in case that nothing is supplied and/or set in the JSON
+        // TODO: Is that an okayish solution with this default value?
+        $this->setMaxAliases(isset($data['maxAliases']) ? $data['maxAliases'] : 0);
+        $this->setMaxMailboxes(isset($data['maxMailboxes']) ? $data['maxMailboxes'] : 0);
+        $this->setMaxQuota(isset($data['maxQuota']) ? $data['maxQuota'] : 0);
+        $this->setUsedQuota(isset($data['usedQuota']) ? $data['usedQuota'] : 0);
+
+        if (isset($data['meta']) && !empty($data['meta'])) {
+            $meta = new Meta();
+            $meta->setResourceType("Domain");
+            $meta->setCreated(isset($data['meta']['created']) ? $data['meta']['created'] : null);
+            $meta->setLastModified(isset($data['meta']['modified']) ? $data['meta']['modified'] : null);
+            $meta->setVersion(isset($data['meta']['version']) ? $data['meta']['version'] : null);
+
+            $this->setMeta($meta);
+        }
+
+        // In case that "active" is not set in the JSON, we set it to true by default
+        // TODO: Is that an okayish solution with this default value?
+        $this->setActive(isset($data['active']) ? boolval($data['active']) : true);
+
+        $this->setSchemas(isset($data['schemas']) ? $data['schemas'] : []);
+    }
+
+    /**
+     * Convert a Domain object to its JSON or array representation
+     *
+     * @param bool $encode A flag indicating if the object should be encoded as JSON
+     * @param string $baseLocation A path indicating the base location of the SCIM server
+     *
+     * @return array|string|false If $encode is true, return either a JSON string or false on failure, else an array
+     */
+    public function toSCIM(bool $encode = true, string $baseLocation = 'http://localhost:8888/v1')
+    {
+        $data = [
+            'id' => $this->getId(),
+            'externalId' => $this->getExternalId(),
+            'schemas' => [Util::DOMAIN_SCHEMA],
+            'meta' => null !== $this->getMeta() ? [
+                'resourceType' => null !== $this->getMeta()->getResourceType()
+                    ? $this->getMeta()->getResourceType() : null,
+                'created' => null !== $this->getMeta()->getCreated() ? $this->getMeta()->getCreated() : null,
+                'updated' => null !== $this->getMeta()->getLastModified() ? $this->getMeta()->getLastModified() : null,
+                'location' => $baseLocation . '/Domains/' . $this->getId(),
+                'version' => null !== $this->getMeta()->getVersion() ? $this->getMeta()->getVersion() : null
+            ] : null,
+            'domainName' => null !== $this->getDomainName() ? $this->getDomainName() : null,
+            'description' => null !== $this->getDescription() ? $this->getDescription() : null,
+            'maxAliases' => $this->getMaxAliases(),
+            'maxMailboxes' => $this->getMaxMailboxes(),
+            'maxQuota' => $this->getMaxQuota(),
+            'usedQuota' => $this->getUsedQuota(),
+            'active' => $this->getActive()
+        ];
+
+        if ($encode) {
+            $data = json_encode($data);
+        }
+
+        return $data;
+    }
 }
diff --git a/src/Models/SCIM/Standard/Filters/AttributeExpression.php b/src/Models/SCIM/Standard/Filters/AttributeExpression.php
new file mode 100644
index 0000000..aec5ddd
--- /dev/null
+++ b/src/Models/SCIM/Standard/Filters/AttributeExpression.php
@@ -0,0 +1,89 @@
+<?php
+
+namespace Opf\Models\SCIM\Standard\Filters;
+
+class AttributeExpression extends FilterExpression
+{
+    /** @var string $attributePath */
+    private $attributePath;
+
+    /** @var \Opf\Models\SCIM\Standard\Filters\AttributeOperator $compareOperator */
+    private $compareOperator;
+
+    /** @var bool|string|int|null $comparisonValue */
+    private $comparisonValue;
+
+    public function __construct($attributePath, $compareOperator, $comparisonValue)
+    {
+        if (isset($attributePath) && !empty($attributePath) && is_string($attributePath)) {
+            $this->attributePath = $attributePath;
+        } else {
+            throw new FilterException(
+                "Attribute path passed to Attribute Expression was either empty, null or not a string"
+            );
+        }
+
+        switch ($compareOperator) {
+            case "eq":
+                $this->compareOperator = AttributeOperator::OP_EQ;
+                break;
+
+            case "ne":
+                $this->compareOperator = AttributeOperator::OP_NE;
+                break;
+
+            case "co":
+                $this->compareOperator = AttributeOperator::OP_CO;
+                break;
+
+            case "sw":
+                $this->compareOperator = AttributeOperator::OP_SW;
+                break;
+
+            case "ew":
+                $this->compareOperator = AttributeOperator::OP_EW;
+                break;
+
+            case "gt":
+                $this->compareOperator = AttributeOperator::OP_GT;
+                break;
+
+            case "lt":
+                $this->compareOperator = AttributeOperator::OP_LT;
+                break;
+
+            case "ge":
+                $this->compareOperator = AttributeOperator::OP_GE;
+                break;
+
+            case "le":
+                $this->compareOperator = AttributeOperator::OP_LE;
+                break;
+
+            case "pr":
+                $this->compareOperator = AttributeOperator::OP_PR;
+                break;
+
+            default:
+                throw new FilterException("Invalid AttributeOperation passed to AttributeExpression");
+                break;
+        }
+
+        $this->comparisonValue = $comparisonValue;
+    }
+
+    public function getAttributePath()
+    {
+        return $this->attributePath;
+    }
+
+    public function getCompareOperator()
+    {
+        return $this->compareOperator;
+    }
+
+    public function getComparisonValue()
+    {
+        return $this->comparisonValue;
+    }
+}
diff --git a/src/Models/SCIM/Standard/Filters/AttributeOperator.php b/src/Models/SCIM/Standard/Filters/AttributeOperator.php
new file mode 100644
index 0000000..dd5d2be
--- /dev/null
+++ b/src/Models/SCIM/Standard/Filters/AttributeOperator.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace Opf\Models\SCIM\Standard\Filters;
+
+class AttributeOperator
+{
+    public const OP_EQ = 1;
+    public const OP_NE = 2;
+    public const OP_CO = 3;
+    public const OP_SW = 4;
+    public const OP_EW = 5;
+    public const OP_PR = 6;
+    public const OP_GT = 7;
+    public const OP_GE = 8;
+    public const OP_LT = 9;
+    public const OP_LE = 10;
+}
diff --git a/src/Models/SCIM/Standard/Filters/FilterException.php b/src/Models/SCIM/Standard/Filters/FilterException.php
new file mode 100644
index 0000000..620a7a1
--- /dev/null
+++ b/src/Models/SCIM/Standard/Filters/FilterException.php
@@ -0,0 +1,9 @@
+<?php
+
+namespace Opf\Models\SCIM\Standard\Filters;
+
+use Exception;
+
+class FilterException extends Exception
+{
+}
diff --git a/src/Models/SCIM/Standard/Filters/FilterExpression.php b/src/Models/SCIM/Standard/Filters/FilterExpression.php
new file mode 100644
index 0000000..dc59428
--- /dev/null
+++ b/src/Models/SCIM/Standard/Filters/FilterExpression.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Opf\Models\SCIM\Standard\Filters;
+
+/**
+ * Base class that represents different types of filter expresssion
+ * (e.g., attribute expressions, logical expressions, etc.)
+ *
+ * See https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+ */
+class FilterExpression
+{
+}
diff --git a/src/Models/SCIM/Standard/Groups/CoreGroup.php b/src/Models/SCIM/Standard/Groups/CoreGroup.php
index c5f40c4..8127b47 100644
--- a/src/Models/SCIM/Standard/Groups/CoreGroup.php
+++ b/src/Models/SCIM/Standard/Groups/CoreGroup.php
@@ -5,6 +5,7 @@ namespace Opf\Models\SCIM\Standard\Groups;
 use Opf\Util\Util;
 use Opf\Models\SCIM\Standard\CommonEntity;
 use Opf\Models\SCIM\Standard\Meta;
+use Opf\Models\SCIM\Standard\MultiValuedAttribute;
 
 class CoreGroup extends CommonEntity
 {
@@ -47,14 +48,27 @@ class CoreGroup extends CommonEntity
         $this->setDisplayName(isset($data['displayName']) ? $data['displayName'] : null);
 
         $meta = new Meta();
-        if (isset($data['meta']) && isset($data['meta']['created'])) {
+        // This is currently commented out, since the code complains about wrongly
+        // formatted timestamps sometimes when fromSCIM is called
+        // TODO: Need to possibly refactor string2datetime and/or dateTime2string in order to fix this
+        /*if (isset($data['meta']) && isset($data['meta']['created'])) {
             $meta->setCreated(Util::string2dateTime($data['meta']['created']));
         } else {
             $meta->setCreated(Util::dateTime2string(new \DateTime('NOW')));
-        }
+        }*/
         $this->setMeta($meta);
 
-        $this->setMembers(isset($data['members']) ? $data['members'] : true);
+        if (isset($data['members'])) {
+            $members = [];
+            foreach ($data['members'] as $member) {
+                $scimMember = new MultiValuedAttribute();
+                $scimMember->setValue($member);
+                $members[] = $scimMember;
+            }
+            $this->setMembers($members);
+        } else {
+            $this->setMembers(null);
+        }
 
         $this->setExternalId(isset($data['externalId']) ? $data['externalId'] : null);
     }
@@ -65,17 +79,18 @@ class CoreGroup extends CommonEntity
             'schemas' => [Util::GROUP_SCHEMA],
             'id' => $this->getId(),
             'externalId' => $this->getExternalId(),
-            'meta' => [
-                'resourceType' => $this->getMeta()->getResourceType(),
-                'created' => $this->getMeta()->getCreated(),
+            'meta' => null !== $this->getMeta() ? [
+                'resourceType' => null !== $this->getMeta()->getResourceType()
+                    ? $this->getMeta()->getResourceType() : null,
+                'created' => null !== $this->getMeta()->getCreated() ? $this->getMeta()->getCreated() : null,
                 'location' => $baseLocation . '/Groups/' . $this->getId(),
-                'version' => $this->getMeta()->getVersion()
-            ],
+                'version' => null !== $this->getMeta()->getVersion() ? $this->getMeta()->getVersion() : null
+            ] : null,
             'displayName' => $this->getDisplayName(),
             'members' => $this->getMembers()
         ];
 
-        if (null !== $this->getMeta()->getLastModified()) {
+        if (null !== $this->getMeta() && null !== $this->getMeta()->getLastModified()) {
             $data['meta']['updated'] = $this->getMeta()->getLastModified();
         }
 
diff --git a/src/Models/SCIM/Standard/Users/CoreUser.php b/src/Models/SCIM/Standard/Users/CoreUser.php
index a5de57d..6807124 100644
--- a/src/Models/SCIM/Standard/Users/CoreUser.php
+++ b/src/Models/SCIM/Standard/Users/CoreUser.php
@@ -299,19 +299,38 @@ class CoreUser extends CommonEntity
         $this->setUserName(isset($data['userName']) ? $data['userName'] : null);
 
         $name = new Name();
-        $name->setFamilyName($data['name']['familyName']);
-        $name->setFormatted($data['name']['formatted']);
-        $name->setGivenName($data['name']['givenName']);
-        $name->setHonorificPrefix($data['name']['honorificPrefix']);
-        $name->setHonorificSuffix($data['name']['honorificSuffix']);
+        if (isset($data['name']) && !empty($data['name'])) {
+            if (isset($data['name']['familyName']) && !empty($data['name']['familyName'])) {
+                $name->setFamilyName($data['name']['familyName']);
+            }
+
+            if (isset($data['name']['formatted']) && !empty($data['name']['formatted'])) {
+                $name->setFormatted($data['name']['formatted']);
+            }
+
+            if (isset($data['name']['givenName']) && !empty($data['name']['givenName'])) {
+                $name->setGivenName($data['name']['givenName']);
+            }
+
+            if (isset($data['name']['honorificPrefix']) && !empty($data['name']['honorificPrefix'])) {
+                $name->setHonorificPrefix($data['name']['honorificPrefix']);
+            }
+
+            if (isset($data['name']['honorificSuffix']) && !empty($data['name']['honorificSuffix'])) {
+                $name->setHonorificSuffix($data['name']['honorificSuffix']);
+            }
+        }
         $this->setName($name);
 
         $meta = new Meta();
-        if (isset($data['meta']) && isset($data['meta']['created'])) {
+        // This is currently commented out, since the code complains about wrongly
+        // formatted timestamps sometimes when fromSCIM is called
+        // TODO: Need to possibly refactor string2datetime and/or dateTime2string in order to fix this
+        /*if (isset($data['meta']) && isset($data['meta']['created'])) {
             $meta->setCreated(Util::string2dateTime($data['meta']['created']));
         } else {
             $meta->setCreated(Util::dateTime2string(new \DateTime('NOW')));
-        }
+        }*/
         $this->setMeta($meta);
 
         $this->setActive(isset($data['active']) ? $data['active'] : true);
@@ -377,7 +396,7 @@ class CoreUser extends CommonEntity
             'preferredLanguage' => $this->getPreferredLanguage(),
             'locale' => $this->getLocale(),
             'timezone' => $this->getTimezone(),
-            'active' => $this->getActive(),
+            'active' => boolval($this->getActive()),
             'password' => $this->getPassword(),
             'emails' => $this->getEmails(),
             'phoneNumbers' => $this->getPhoneNumbers(),
diff --git a/src/Repositories/Groups/MockGroupsRepository.php b/src/Repositories/Groups/MockGroupsRepository.php
index 60ecd7c..2551c25 100644
--- a/src/Repositories/Groups/MockGroupsRepository.php
+++ b/src/Repositories/Groups/MockGroupsRepository.php
@@ -2,136 +2,106 @@
 
 namespace Opf\Repositories\Groups;
 
+use Monolog\Logger;
 use Opf\Models\SCIM\Standard\Groups\CoreGroup;
 use Opf\Models\SCIM\Standard\Meta;
 use Opf\Repositories\Repository;
+use Opf\Util\Filters\FilterUtil;
 use Psr\Container\ContainerInterface;
 
 class MockGroupsRepository extends Repository
 {
+    private $logger;
+
     public function __construct(ContainerInterface $container)
     {
         parent::__construct($container);
         $this->dataAccess = $this->container->get('GroupsDataAccess');
         $this->adapter = $this->container->get('GroupsAdapter');
+        $this->logger = $this->container->get(Logger::class);
     }
 
-    public function getAll(): array
-    {
+    public function getAll(
+        $filter = '',
+        $startIndex = 0,
+        $count = 0,
+        $attributes = [],
+        $excludedAttributes = []
+    ): array {
         // Read all mock groups from the database
-        $mockGroups = $this->dataAccess::all();
+        $mockGroups = $this->dataAccess->getAll();
         $scimGroups = [];
 
-        // Transform each mock group to a SCIM group via the injected adapter
         foreach ($mockGroups as $mockGroup) {
-            $this->adapter->setGroup($mockGroup);
-
-            $scimGroup = new CoreGroup();
-            $scimGroup->setId($this->adapter->getId());
-            $scimGroup->setDisplayName($this->adapter->getDisplayName());
-            $scimGroup->setMembers($this->adapter->getMembers());
-
-            $scimGroupMeta = new Meta();
-            $scimGroupMeta->setCreated($this->adapter->getCreatedAt());
-
-            $scimGroup->setMeta($scimGroupMeta);
-
+            $scimGroup = $this->adapter->getCoreGroup($mockGroup);
             $scimGroups[] = $scimGroup;
         }
 
+        if (isset($filter) && !empty($filter)) {
+            $scimGroupsToFilter = [];
+            foreach ($scimGroups as $scimGroup) {
+                $scimGroupsToFilter[] = $scimGroup->toSCIM(false);
+            }
+
+            $filteredScimData = FilterUtil::performFiltering($filter, $scimGroupsToFilter);
+
+            $scimGroups = [];
+            foreach ($filteredScimData as $filteredScimGroup) {
+                $scimGroup = new CoreGroup();
+                $scimGroup->fromSCIM($filteredScimGroup);
+                $scimGroups[] = $scimGroup;
+            }
+
+            return $scimGroups;
+        }
+
         return $scimGroups;
     }
 
-    public function getOneById(string $id): ?CoreGroup
-    {
-        if (isset($id) && !empty($id)) {
-            $mockGroup = $this->dataAccess::find($id);
-
-            if (isset($mockGroup) && !empty($mockGroup)) {
-                $this->adapter->setGroup($mockGroup);
-
-                $scimGroup = new CoreGroup();
-                $scimGroup->setId($this->adapter->getId());
-                $scimGroup->setDisplayName($this->adapter->getDisplayName());
-                $scimGroup->setMembers($this->adapter->getMembers());
-
-                $scimGroupMeta = new Meta();
-                $scimGroupMeta->setCreated($this->adapter->getCreatedAt());
-
-                $scimGroup->setMeta($scimGroupMeta);
-
-                return $scimGroup;
-            } else {
-                return null;
-            }
-        } else {
-            return null;
-        }
+    public function getOneById(
+        string $id,
+        $filter = '',
+        $startIndex = 0,
+        $count = 0,
+        $attributes = [],
+        $excludedAttributes = []
+    ): ?CoreGroup {
+        $mockGroup = $this->dataAccess->getOneById($id);
+        return $this->adapter->getCoreGroup($mockGroup);
     }
 
     public function create($object): ?CoreGroup
     {
-        if (isset($object) && !empty($object)) {
-            $scimGroup = new CoreGroup();
-            $scimGroup->fromSCIM($object);
+        $scimGroupToCreate = new CoreGroup();
+        $scimGroupToCreate->fromSCIM($object);
 
-            $this->adapter->setGroup($this->dataAccess);
+        $mockGroupToCreate = $this->adapter->getMockGroup($scimGroupToCreate);
 
-            $this->adapter->setId($scimGroup->getId());
-            $this->adapter->setDisplayName($scimGroup->getDisplayName());
-            $this->adapter->setMembers($scimGroup->getMembers());
-            $this->adapter->setCreatedAt($scimGroup->getMeta()->getCreated());
+        $mockGroupCreated = $this->dataAccess->create($mockGroupToCreate);
 
-            $this->dataAccess = $this->adapter->getGroup();
-            if ($this->dataAccess->save()) {
-                return $scimGroup;
-            } else {
-                return null;
-            }
+        if (isset($mockGroupCreated)) {
+            return $this->adapter->getCoreGroup($mockGroupCreated);
         }
+        return null;
     }
 
     public function update(string $id, $object): ?CoreGroup
     {
-        if (isset($id) && !empty($id)) {
-            $mockGroup = $this->dataAccess::find($id);
-            if (isset($mockGroup) && !empty($mockGroup)) {
-                $scimGroup = new CoreGroup();
-                $scimGroup->fromSCIM($object);
+        $scimGroupToUpdate = new CoreGroup();
+        $scimGroupToUpdate->fromSCIM($object);
 
-                $this->adapter->setGroup($mockGroup);
+        $mockGroupToUpdate = $this->adapter->getMockGroup($scimGroupToUpdate);
 
-                $scimGroup->setId($this->adapter->getId());
+        $mockGroupUpdated = $this->dataAccess->update($id, $mockGroupToUpdate);
 
-                $this->adapter->setDisplayName($scimGroup->getDisplayName());
-                $this->adapter->setMembers($scimGroup->getMembers());
-                $this->adapter->setCreatedAt($scimGroup->getMeta()->getCreated());
-
-                $mockGroup = $this->adapter->getGroup();
-                if ($mockGroup->save()) {
-                    return $scimGroup;
-                } else {
-                    return null;
-                }
-            } else {
-                return null;
-            }
-        } else {
-            return null;
+        if (isset($mockGroupUpdated)) {
+            return $this->adapter->getCoreGroup($mockGroupUpdated);
         }
+        return null;
     }
 
     public function delete(string $id): bool
     {
-        if (isset($id) && !empty($id)) {
-            $mockGroup = $this->dataAccess::find($id);
-            if (!isset($mockGroup) || empty($mockGroup)) {
-                return false;
-            }
-            $mockGroup->delete();
-            return true;
-        } else {
-            return false;
-        }
+        return $this->dataAccess->delete($id);
     }
 }
diff --git a/src/Repositories/Repository.php b/src/Repositories/Repository.php
index 7a11484..18ac25b 100644
--- a/src/Repositories/Repository.php
+++ b/src/Repositories/Repository.php
@@ -15,9 +15,68 @@ abstract class Repository
         $this->container = $container;
     }
 
-    abstract public function getAll(): array;
-    abstract public function getOneById(string $id): ?object;
+    /**
+     * @param string $filter Optional parameter which contains a filter expression
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+     *
+     * @param int $startIndex Optional parameter for specifying the start index, used for pagination
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.4
+     *
+     * @param int $count Optional parameter for specifying the number of results, used for pagination
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.4
+     *
+     * @param array $attributes Optional parameter for including only specific attributes in the response
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.5
+     *  (if $exludedAttributes is not empty, this should be empty)
+     *
+     * @param array $excludedAttributes Optional parameter for excluding specific attributes from the response
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.5
+     *  (if $attributes is not empty, this should be empty)
+     *
+     * @return array An array of SCIM resources
+     */
+    abstract public function getAll(
+        $filter = '',
+        $startIndex = 0,
+        $count = 0,
+        $attributes = [],
+        $excludedAttributes = []
+    ): array;
+
+    /**
+     * @param string $id Required parameter which contains of a given entity that should be retrieved
+     *
+     * @param string $filter Optional parameter which contains a filter expression
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+     *
+     * @param int $startIndex Optional parameter for specifying the start index, used for pagination
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.4
+     *
+     * @param int $count Optional parameter for specifying the number of results, used for pagination
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.4
+     *
+     * @param array $attributes Optional parameter for including only specific attributes in the response
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.5
+     *  (if $exludedAttributes is not empty, this should be empty)
+     *
+     * @param array $excludedAttributes Optional parameter for excluding specific attributes from the response
+     *  as per https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.5
+     *  (if $attributes is not empty, this should be empty)
+     *
+     * @return object|null A SCIM resource or null if no resource found
+     */
+    abstract public function getOneById(
+        string $id,
+        $filter = '',
+        $startIndex = 0,
+        $count = 0,
+        $attributes = [],
+        $excludedAttributes = []
+    ): ?object;
+
     abstract public function create($object): ?object;
+
     abstract public function update(string $id, $object): ?object;
+
     abstract public function delete(string $id): bool;
 }
diff --git a/src/Repositories/Users/MockUsersRepository.php b/src/Repositories/Users/MockUsersRepository.php
index 2e4bd5e..3f2d380 100644
--- a/src/Repositories/Users/MockUsersRepository.php
+++ b/src/Repositories/Users/MockUsersRepository.php
@@ -2,190 +2,120 @@
 
 namespace Opf\Repositories\Users;
 
+use Monolog\Logger;
 use Opf\Models\SCIM\Standard\Users\CoreUser;
 use Opf\Models\SCIM\Standard\Meta;
 use Opf\Repositories\Repository;
+use Opf\Util\Filters\FilterUtil;
 use Psr\Container\ContainerInterface;
 
 class MockUsersRepository extends Repository
 {
+    private $logger;
+
     public function __construct(ContainerInterface $container)
     {
         parent::__construct($container);
         $this->dataAccess = $this->container->get('UsersDataAccess');
         $this->adapter = $this->container->get('UsersAdapter');
+        $this->logger = $this->container->get(Logger::class);
     }
-    public function getAll(): array
-    {
+
+    public function getAll(
+        $filter = '',
+        $startIndex = 0,
+        $count = 0,
+        $attributes = [],
+        $excludedAttributes = []
+    ): array {
         // Read all mock users from the database
-        $mockUsers = $this->dataAccess::all();
+        $mockUsers = $this->dataAccess->getAll();
         $scimUsers = [];
 
-        // Transform each mock user to a SCIM user via the injected adapter
         foreach ($mockUsers as $mockUser) {
-            // TODO: Possibly refactor the transformation logic between SCIM users and other users
-            // in a separate method or class, since it seems to be rather repetitive
-            $this->adapter->setUser($mockUser);
-
-            $scimUser = new CoreUser();
-            $scimUser->setId($this->adapter->getId());
-            $scimUser->setUserName($this->adapter->getUserName());
-
-            $scimUserMeta = new Meta();
-            $scimUserMeta->setCreated($this->adapter->getCreatedAt());
-
-            $scimUser->setMeta($scimUserMeta);
-            $scimUser->setActive($this->adapter->getActive());
-            $scimUser->setExternalId($this->adapter->getExternalId());
-            $scimUser->setProfileUrl($this->adapter->getProfileUrl());
-
+            $scimUser = $this->adapter->getCoreUser($mockUser);
             $scimUsers[] = $scimUser;
         }
 
+        if (isset($filter) && !empty($filter)) {
+            $scimUsersToFilter = [];
+            foreach ($scimUsers as $scimUser) {
+                $scimUsersToFilter[] = $scimUser->toSCIM(false);
+            }
+
+            $filteredScimData = FilterUtil::performFiltering($filter, $scimUsersToFilter);
+
+            $scimUsers = [];
+            foreach ($filteredScimData as $filteredScimUser) {
+                $scimUser = new CoreUser();
+                $scimUser->fromSCIM($filteredScimUser);
+                $scimUsers[] = $scimUser;
+            }
+
+            return $scimUsers;
+        }
+
         return $scimUsers;
     }
 
-    public function getOneByUserName(string $userName): ?CoreUser
-    {
-        if (isset($userName) && !empty($userName)) {
-            // Try to find the first user from the database with the supplied username
-            $mockUser = $this->dataAccess::where('userName', $userName)->first();
+    public function getOneById(
+        string $id,
+        $filter = '',
+        $startIndex = 0,
+        $count = 0,
+        $attributes = [],
+        $excludedAttributes = []
+    ): ?CoreUser {
+        $mockUser = $this->dataAccess->getOneById($id);
+        $scimUser = $this->adapter->getCoreUser($mockUser);
 
-            // If such a user exists, map it to a SCIM user and return the SCIM user
-            if (isset($mockUser) && !empty($mockUser)) {
-                $this->adapter->setUser($mockUser);
+        if (isset($filter) && !empty($filter)) {
+            // Pass the single user as an array of an array, representing the user
+            $scimUsersToFilter = array($scimUser->toSCIM(false));
+            $filteredScimData = FilterUtil::performFiltering($filter, $scimUsersToFilter);
 
+            if (!empty($filteredScimData)) {
                 $scimUser = new CoreUser();
-                $scimUser->setId($this->adapter->getId());
-                $scimUser->setUserName($this->adapter->getUserName());
-
-                $scimUserMeta = new Meta();
-                $scimUserMeta->setCreated($this->adapter->getCreatedAt());
-
-                $scimUser->setMeta($scimUserMeta);
-                $scimUser->setActive($this->adapter->getActive());
-                $scimUser->setExternalId($this->adapter->getExternalId());
-                $scimUser->setProfileUrl($this->adapter->getProfileUrl());
-
+                $scimUser->fromSCIM($filteredScimData[0]);
                 return $scimUser;
-            } else {
-                return null;
             }
         }
-    }
 
-    public function getOneById(string $id): ?CoreUser
-    {
-        if (isset($id) && !empty($id)) {
-            // Try to find a user from the database with the supplied ID
-            $mockUser = $this->dataAccess::find($id);
-
-            // If there's such a user, transform it to a SCIM user and return the SCIM user
-            if (isset($mockUser) && !empty($mockUser)) {
-                $this->adapter->setUser($mockUser);
-
-                $scimUser = new CoreUser();
-                $scimUser->setId($this->adapter->getId());
-                $scimUser->setUserName($this->adapter->getUserName());
-
-                $scimUserMeta = new Meta();
-                $scimUserMeta->setCreated($this->adapter->getCreatedAt());
-
-                $scimUser->setMeta($scimUserMeta);
-                $scimUser->setActive($this->adapter->getActive());
-                $scimUser->setExternalId($this->adapter->getExternalId());
-                $scimUser->setProfileUrl($this->adapter->getProfileUrl());
-
-                return $scimUser;
-            } else {
-                return null;
-            }
-        } else {
-            return null;
-        }
+        return $scimUser;
     }
 
     public function create($object): ?CoreUser
     {
-        if (isset($object) && !empty($object)) {
-            // Transform the incoming JSON user object to a SCIM object
-            // Then transform the SCIM object to a mock user that can be stored in the database
-            $scimUser = new CoreUser();
-            $scimUser->fromSCIM($object);
+        $scimUserToCreate = new CoreUser();
+        $scimUserToCreate->fromSCIM($object);
 
-            // $this->dataAccess represents an instance of the MockUser ORM model
-            // that we use for user storage to and retrieval from SQLite
-            $this->adapter->setUser($this->dataAccess);
+        $mockUserToCreate = $this->adapter->getMockUser($scimUserToCreate);
 
-            $this->adapter->setId($scimUser->getId());
-            $this->adapter->setUserName($scimUser->getUserName());
-            $this->adapter->setCreatedAt($scimUser->getMeta()->getCreated());
-            $this->adapter->setActive($scimUser->getActive());
-            $this->adapter->setExternalId($scimUser->getExternalId());
-            $this->adapter->setProfileUrl($scimUser->getProfileUrl());
+        $mockUserCreated = $this->dataAccess->create($mockUserToCreate);
 
-            // Obtain the transformed mock user from the adapter and try to save it to the database
-            $this->dataAccess = $this->adapter->getUser();
-            if ($this->dataAccess->save()) {
-                return $scimUser;
-            } else {
-                return null;
-            }
+        if (isset($mockUserCreated)) {
+            return $this->adapter->getCoreUser($mockUserCreated);
         }
+        return null;
     }
 
     public function update(string $id, $object): ?CoreUser
     {
-        if (isset($id) && !empty($id)) {
-            // Try to find the user with the supplied ID
-            $mockUser = $this->dataAccess::find($id);
-            if (isset($mockUser) && !empty($mockUser)) {
-                // Transform the received JSON user object to a SCIM object
-                $scimUser = new CoreUser();
-                $scimUser->fromSCIM($object);
+        $scimUserToUpdate = new CoreUser();
+        $scimUserToUpdate->fromSCIM($object);
 
-                // Set the adapter's internal user object to the found user from the database
-                $this->adapter->setUser($mockUser);
+        $mockUserToUpdate = $this->adapter->getMockUser($scimUserToUpdate);
 
-                // Set the SCIM user's ID to be the same as the ID of the found user from the database
-                // Otherwise, we might lose the ID if a new one is supplied in the request
-                $scimUser->setId($this->adapter->getId());
+        $mockUserUpdated = $this->dataAccess->update($id, $mockUserToUpdate);
 
-                // Transform the SCIM object to a mock user via the adapter and replace
-                // any properties of the mock user with the new properties incoming via the SCIM object
-                $this->adapter->setUserName($scimUser->getUserName());
-                $this->adapter->setCreatedAt($scimUser->getMeta()->getCreated());
-                $this->adapter->setActive($scimUser->getActive());
-                $this->adapter->setExternalId($scimUser->getExternalId());
-                $this->adapter->setProfileUrl($scimUser->getProfileUrl());
-
-                // Obtain the updated mock user via the adapter and try to save it to the database
-                $mockUser = $this->adapter->getUser();
-                if ($mockUser->save()) {
-                    return $scimUser;
-                } else {
-                    return null;
-                }
-            } else {
-                return null;
-            }
-        } else {
-            return null;
+        if (isset($mockUserUpdated)) {
+            return $this->adapter->getCoreUser($mockUserUpdated);
         }
+        return null;
     }
 
     public function delete(string $id): bool
     {
-        if (isset($id) && !empty($id)) {
-            // Try to find the user to be deleted
-            $mockUser = $this->dataAccess::find($id);
-            if (!isset($mockUser) || empty($mockUser)) {
-                return false;
-            }
-            $mockUser->delete();
-            return true;
-        } else {
-            return false;
-        }
+        return $this->dataAccess->delete($id);
     }
 }
diff --git a/src/Repositories/Users/PfaUsersRepository.php b/src/Repositories/Users/PfaUsersRepository.php
deleted file mode 100644
index 4c8cff7..0000000
--- a/src/Repositories/Users/PfaUsersRepository.php
+++ /dev/null
@@ -1,78 +0,0 @@
-<?php
-
-namespace Opf\Repositories\Users;
-
-use Opf\Models\SCIM\Custom\Users\ProvisioningUser;
-use Opf\Models\SCIM\Standard\Meta;
-use Opf\Models\SCIM\Standard\MultiValuedAttribute;
-use Opf\Repositories\Repository;
-use Opf\Util\Util;
-use Psr\Container\ContainerInterface;
-use Monolog\Logger;
-
-class PfaUsersRepository extends Repository
-{
-    private $logger;
-
-    public function __construct(ContainerInterface $container)
-    {
-        parent::__construct($container);
-        $this->dataAccess = $this->container->get('UsersDataAccess');
-        $this->adapter = $this->container->get('UsersAdapter');
-        $this->logger = $this->container->get(Logger::class);
-    }
-
-    public function getAll(): array
-    {
-        $pfaUsers = $this->dataAccess->getAll();
-        $scimUsers = [];
-
-        foreach ($pfaUsers as $pfaUser) {
-            $scimUser = $this->adapter->getProvisioningUser($pfaUser);
-            $scimUsers[] = $scimUser;
-        }
-
-        return $scimUsers;
-    }
-
-    public function getOneById(string $id): ?ProvisioningUser
-    {
-        $pfaUser = $this->dataAccess->getOneById($id);
-        return $this->adapter->getProvisioningUser($pfaUser);
-    }
-
-    public function create($object): ?ProvisioningUser
-    {
-        $scimUserToCreate = new ProvisioningUser();
-        $scimUserToCreate->fromSCIM($object);
-
-        $pfaUserToCreate = $this->adapter->getPfaUser($scimUserToCreate);
-
-        $pfaUserCreated = $this->dataAccess->create($pfaUserToCreate);
-
-        if (isset($pfaUserCreated)) {
-            return $this->adapter->getProvisioningUser($pfaUserCreated);
-        }
-        return null;
-    }
-
-    public function update(string $id, $object): ?ProvisioningUser
-    {
-        $scimUserToUpdate = new ProvisioningUser();
-        $scimUserToUpdate->fromSCIM($object);
-
-        $pfaUserToUpdate = $this->adapter->getPfaUser($scimUserToUpdate);
-
-        $pfaUserUpdated = $this->dataAccess->update($id, $pfaUserToUpdate);
-
-        if (isset($pfaUserUpdated)) {
-            return $this->adapter->getProvisioningUser($pfaUserUpdated);
-        }
-        return null;
-    }
-
-    public function delete(string $id): bool
-    {
-        return $this->dataAccess->delete($id);
-    }
-}
diff --git a/src/ScimServer.php b/src/ScimServer.php
new file mode 100644
index 0000000..dafdc12
--- /dev/null
+++ b/src/ScimServer.php
@@ -0,0 +1,156 @@
+<?php
+
+namespace Opf;
+
+use DI\ContainerBuilder;
+use Exception;
+use Opf\Handlers\HttpErrorHandler;
+use Opf\Util\Util;
+use Slim\App;
+use Slim\Factory\AppFactory;
+
+class ScimServer
+{
+    /**
+     * @var string $scimServerPhpRoot The root of the project using
+     * OPF as a dependency. This is needed for autoloading purposes,
+     * such that all classes of the project using OPF can be made
+     * visible to OPF.
+     */
+    private string $scimServerPhpRoot;
+
+    /**
+     * A container builder which is used to configure and create a
+     * DI container, used by the Slim application
+     */
+    private ContainerBuilder $containerBuilder;
+
+    /**
+     * The Slim application to configure and run as a server, exposing
+     * the SCIM API
+     */
+    private App $app;
+
+    /**
+     * @var array $dependencies An array holding dependency definitions,
+     * passed to the DI ContainerBuilder for configuring the DI container
+     */
+    private array $dependencies;
+
+    /**
+     * @var array $middleware Any custom middleware that needs to be added
+     * to the Slim application (e.g., custom auth middleware)
+     */
+    private array $middleware;
+
+    /**
+     * ScimServer class constructor
+     *
+     * @param string $scimServerPhpRoot The root of the project using
+     * the OPF library. Needed for autoloading. See more in description
+     * of the dedicated class property of the same name
+     */
+    public function __construct(string $scimServerPhpRoot)
+    {
+        $this->scimServerPhpRoot = $scimServerPhpRoot;
+
+        /**
+         * Once we have the root directory of the project that's using
+         * OPF, we include its autoload file, so that we don't run into
+         * autoloading issues.
+         */
+        require $this->scimServerPhpRoot . '/vendor/autoload.php';
+    }
+
+    public function setConfig(string $configFilePath)
+    {
+        if (!isset($configFilePath) || empty($configFilePath)) {
+            throw new Exception("Config file path must be supplied");
+        }
+
+        Util::setConfigFile($configFilePath);
+    }
+
+    public function setDependencies(array $dependencies = array())
+    {
+        $baseDependencies = require __DIR__ . '/Dependencies/dependencies.php';
+        $this->dependencies = array_merge($baseDependencies, $dependencies);
+    }
+
+    public function setMiddleware(array $middleware = array())
+    {
+        $this->middleware = $middleware;
+    }
+
+    public function run()
+    {
+        session_start();
+
+        // Instantiate the PHP-DI ContainerBuilder
+        $containerBuilder = new ContainerBuilder();
+
+        $config = Util::getConfigFile();
+        if ($config['isInProduction']) {
+            $containerBuilder->enableCompilation(__DIR__ . '/../var/cache');
+        }
+
+        // Set up a few Slim-related settings
+        $settings = [
+            'settings' => [
+                'determineRouteBeforeAppMiddleware' => false,
+                'displayErrorDetails' => true, // set to false in production
+                'addContentLengthHeader' => false, // Allow the web server to send the content-length header
+            ]
+        ];
+        $containerBuilder->addDefinitions($settings);
+
+        // Set all necessary dependencies which are provided in this class'
+        // $dependencies attribute
+        $containerBuilder->addDefinitions($this->dependencies);
+
+        // Build PHP-DI Container instance
+        $container = $containerBuilder->build();
+
+        // Instantiate the app
+        AppFactory::setContainer($container);
+        $this->app = AppFactory::create();
+
+        // Set our app's base path if it's configured
+        if (isset($config['basePath']) && !empty($config['basePath'])) {
+            $this->app->setBasePath($config['basePath']);
+        }
+
+        // Register routes
+        $routes = require __DIR__ . '/routes.php';
+        $routes($this->app);
+
+
+        // Iterate through the custom middleware (if any) and set it
+        if (isset($this->middleware) && !empty($this->middleware)) {
+            foreach ($this->middleware as $middleware) {
+                $this->app->addMiddleware($this->app->getContainer()->get($middleware));
+            }
+        }
+
+        // Add Routing Middleware
+        $this->app->addRoutingMiddleware();
+        $this->app->addBodyParsingMiddleware();
+
+        $callableResolver = $this->app->getCallableResolver();
+        $responseFactory = $this->app->getResponseFactory();
+
+        // Instantiate our custom Http error handler that we need further down below
+        $errorHandler = new HttpErrorHandler($callableResolver, $responseFactory);
+
+        // Add error middleware
+        $errorMiddleware = $this->app->addErrorMiddleware(
+            $config['isInProduction'] ? false : true,
+            true,
+            true
+        );
+        $errorMiddleware->setDefaultErrorHandler($errorHandler);
+
+        // Run app
+        $this->app->run();
+    }
+}
diff --git a/src/Util/Authentication/AuthenticatorInterface.php b/src/Util/Authentication/AuthenticatorInterface.php
new file mode 100644
index 0000000..f897b1a
--- /dev/null
+++ b/src/Util/Authentication/AuthenticatorInterface.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Opf\Util\Authentication;
+
+interface AuthenticatorInterface
+{
+    /**
+     * A method for performing authentication
+     *
+     * @param string $credentials The authentication credentials
+     * @param array $authorizationInfo Array with infor to check if user is authorized to perform a given operation
+     *
+     * @return bool Return true if authentication succeeded, otherwise false
+     */
+    public function authenticate(string $credentials, array $authorizationInfo): bool;
+}
diff --git a/src/Util/Authentication/SimpleBearerAuthenticator.php b/src/Util/Authentication/SimpleBearerAuthenticator.php
new file mode 100644
index 0000000..60a8138
--- /dev/null
+++ b/src/Util/Authentication/SimpleBearerAuthenticator.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Opf\Util\Authentication;
+
+use Exception;
+use Firebase\JWT\JWT;
+use Firebase\JWT\Key;
+use Opf\Util\Util;
+use Psr\Container\ContainerInterface;
+
+class SimpleBearerAuthenticator implements AuthenticatorInterface
+{
+    /** @var \Monolog\Logger */
+    private $logger;
+
+    public function __construct(ContainerInterface $container)
+    {
+        $this->logger = $container->get(\Monolog\Logger::class);    
+    }
+
+    public function authenticate(string $credentials, array $authorizationInfo): bool
+    {
+        $jwtPayload = [];
+        $jwtSecret = Util::getConfigFile()['jwt']['secret'];
+        try {
+            $jwtPayload = (array) JWT::decode($credentials, new Key($jwtSecret, 'HS256'));
+        } catch (Exception $e) {
+            // If we land here, something was wrong with the JWT and auth has thus failed
+            $this->logger->error($e->getMessage());
+            return false;
+        }
+        return true;
+    }
+}
diff --git a/src/Util/Filters/FilterParser.php b/src/Util/Filters/FilterParser.php
new file mode 100644
index 0000000..fb9aa92
--- /dev/null
+++ b/src/Util/Filters/FilterParser.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Opf\Util\Filters;
+
+use Opf\Models\SCIM\Standard\Filters\AttributeExpression;
+use Opf\Models\SCIM\Standard\Filters\FilterException;
+use Opf\Models\SCIM\Standard\Filters\FilterExpression;
+
+/**
+ * A parser for SCIM filter expressions
+ *
+ * Note: currently this parser is very simplistic and directly tries to parse a string, representing a filter expession.
+ * For now only attribute expression are supported: see https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+ * In later iterations, it could be changed, such that it uses a lexer for lexical analysis first and then performs
+ * syntactic analysis, based on the lexer's output.
+ */
+class FilterParser
+{
+    public static function parseFilterExpression(string $filterExpression): FilterExpression
+    {
+        if (!isset($filterExpression) || empty($filterExpression) || !is_string($filterExpression)) {
+            throw new FilterException(
+                "Invalid filter expression passed for parsing: expression was either null, empty or not a string"
+            );
+        }
+
+        $splitFilterExpression = explode(" ", $filterExpression);
+        if (count($splitFilterExpression) < 2 || count($splitFilterExpression) > 3) {
+            throw new FilterException("Incorrectly formatted AttributeExpression");
+        }
+
+        $attributeExpression = new AttributeExpression(
+            $splitFilterExpression[0],
+            $splitFilterExpression[1],
+            $splitFilterExpression[2]
+        );
+
+        return $attributeExpression;
+    }
+}
diff --git a/src/Util/Filters/FilterUtil.php b/src/Util/Filters/FilterUtil.php
new file mode 100644
index 0000000..673bfb1
--- /dev/null
+++ b/src/Util/Filters/FilterUtil.php
@@ -0,0 +1,398 @@
+<?php
+
+namespace Opf\Util\Filters;
+
+use Exception;
+use Opf\Models\SCIM\Standard\Filters\AttributeExpression;
+use Opf\Models\SCIM\Standard\Filters\AttributeOperator;
+use Opf\Models\SCIM\Standard\Filters\FilterException;
+
+class FilterUtil
+{
+    /**
+     * @param string $filterExpression The SCIM filter expression that is to be parsed and applied
+     * @param array $scimData An array of SCIM objects (each represented as an array) that is to be filtered
+     *
+     * @return array Array of filtered SCIM objects (again each represented as an array)
+     */
+    public static function performFiltering(string $filterExpression, array $scimData): array
+    {
+
+        try {
+            $parsedFilterExpression = FilterParser::parseFilterExpression($filterExpression);
+        } catch (Exception $e) {
+            throw $e;
+        }
+
+        $filteredScimData = [];
+
+        // Call appropriate filtering method
+        // For now, we only have a method for filtering, based on AttributeExpression
+        switch (true) {
+            case $parsedFilterExpression instanceof AttributeExpression:
+                $filteredScimData = self::filterWithAttributeExpression($parsedFilterExpression, $scimData);
+                break;
+
+            default:
+                throw new FilterException("Unknown filter expression type");
+                break;
+        }
+
+        return $filteredScimData;
+    }
+
+    private static function filterWithAttributeExpression(
+        AttributeExpression $attributeExpression,
+        array $scimData
+    ): array {
+        // In case of null or an empty array, we return an empty array, since we have nothing to filter
+        if (!isset($scimData) || empty($scimData)) {
+            return [];
+        }
+
+        $filteredScimData = [];
+
+        $attributePath = $attributeExpression->getAttributePath();
+        $compareOperator = $attributeExpression->getCompareOperator();
+        $comparisonValue = $attributeExpression->getComparisonValue();
+
+        // If we have a nested attribute (i.e., an attribute with subattribute(s)),
+        // then we split the attribute path by "." and store all the single parts
+        // in an array
+        // On the other hand (i.e., no nested attribute), we store the attribute path
+        // in an array which only contains the attribute path as a single element
+        if (strpos($attributePath, ".") !== false) {
+            $attributePath = explode(".", $attributePath);
+        } else {
+            $attributePath = array($attributePath);
+        }
+
+        // Decide which filter function to call, based on the comparison operator
+        $filterFunctionToUse = null;
+
+        switch ($compareOperator) {
+            case AttributeOperator::OP_EQ:
+                $filterFunctionToUse = "stringEqualsFilter";
+                break;
+
+            case AttributeOperator::OP_NE:
+                $filterFunctionToUse = "stringNotEqualsFilter";
+                break;
+
+            case AttributeOperator::OP_CO:
+                $filterFunctionToUse = "stringContainsFilter";
+                break;
+
+            case AttributeOperator::OP_SW:
+                $filterFunctionToUse = "stringStartsWithFilter";
+                break;
+
+            case AttributeOperator::OP_EW:
+                $filterFunctionToUse = "stringEndsWithFilter";
+                break;
+
+            case AttributeOperator::OP_PR:
+                if (isset($comparisonValue) && !empty($comparisonValue)) {
+                    throw new FilterException("\"pr\" filter operator must be used without a comparison value");
+                    break;
+                } else {
+                    $filterFunctionToUse = "hasValueFilter";
+                    break;
+                }
+
+            case AttributeOperator::OP_GT:
+                $filterFunctionToUse = "greaterThanFilter";
+                break;
+
+            case AttributeOperator::OP_GE:
+                $filterFunctionToUse = "greaterThanOrEqualToFilter";
+                break;
+
+            case AttributeOperator::OP_LT:
+                $filterFunctionToUse = "lessThanFilter";
+                break;
+
+            case AttributeOperator::OP_LE:
+                $filterFunctionToUse = "lessThanOrEqualToFilter";
+                break;
+
+            default:
+                throw new FilterException("Unknown comparison operator found");
+                break;
+        }
+
+        // Put the function to call in a variable that we can use for calls below
+        $filterFunctionToUse = array(FilterUtil::class, $filterFunctionToUse);
+
+        foreach ($scimData as $scimObject) {
+            // Obtain the attribute of the SCIM objects that we want to filter for
+            $attribute = $scimObject;
+            foreach ($attributePath as $attributePathComponent) {
+                if (array_key_exists($attributePathComponent, $attribute)) {
+                    $attribute = $attribute[$attributePathComponent];
+                } else {
+                    throw new FilterException(
+                        "Attribute " . $attributePathComponent .
+                        " to filter by is undefined for the given SCIM resources"
+                    );
+                }
+            }
+
+            $filterResult = false;
+            // If the filter function to call is "hasValueFilter", we need to pass it only the attribute
+            if (strcmp($filterFunctionToUse[1], "hasValueFilter") === 0) {
+                $filterResult = $filterFunctionToUse($attribute);
+            } else {
+                $filterResult = $filterFunctionToUse($attribute, $comparisonValue);
+            }
+
+            if ($filterResult) {
+                $filteredScimData[] = $scimObject;
+            }
+        }
+
+        return $filteredScimData;
+    }
+
+    private static function stringEqualsFilter($attribute, $comparisonValue)
+    {
+        if (strcmp($attribute, $comparisonValue) === 0) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static function stringNotEqualsFilter($attribute, $comparisonValue)
+    {
+        if (strcmp($attribute, $comparisonValue) !== 0) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static function stringContainsFilter($attribute, $comparisonValue)
+    {
+        if (strpos($attribute, $comparisonValue) !== false) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static function stringStartsWithFilter($attribute, $comparisonValue)
+    {
+        if (substr($attribute, 0, strlen($comparisonValue)) === $comparisonValue) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static function stringEndsWithFilter($attribute, $comparisonValue)
+    {
+        if (substr($attribute, -strlen($comparisonValue)) === $comparisonValue) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static function hasValueFilter($attribute)
+    {
+        if (isset($attribute) && !empty($attribute)) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private static function greaterThanFilter($attribute, $comparisonValue)
+    {
+        $comparisonValueType = gettype($comparisonValue);
+
+        $attributeType = gettype($attribute);
+
+        // First, make sure that the attribute and the comparison value have the same type
+        if (strcmp($attributeType, $comparisonValueType) !== 0) {
+            throw new FilterException(
+                "\"gt\" filter operator requires the attribute and the comparison value to be of the same type"
+            );
+        }
+
+        switch ($attributeType) {
+            case "string":
+                // Try to parse string to date to see if we need to compare timestamps
+                if (
+                    strtotime($attribute) !== false
+                    && strtotime($comparisonValue) !== false
+                ) {
+                    if (strtotime($attribute) > strtotime($comparisonValue)) {
+                        return true;
+                    }
+                } else { // If not date, but just regular string, then perform lexicographic comparison
+                    if (strcasecmp($attribute, $comparisonValue) > 0) {
+                        return true;
+                    }
+                }
+                break;
+
+            case "integer":
+                if ($attribute > $comparisonValue) {
+                    return true;
+                }
+                break;
+
+            // For any other data type, throw an exception
+            // TODO: Return 400 with "scimType" of "invalidFilter" as per
+            // https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+            default:
+                throw new FilterException("Unsupported type for \"gt\" operation");
+                break;
+        }
+
+        return false;
+    }
+
+    private static function greaterThanOrEqualToFilter($attribute, $comparisonValue)
+    {
+        $comparisonValueType = gettype($comparisonValue);
+
+        $attributeType = gettype($attribute);
+
+        // First, make sure that the attribute and the comparison value have the same type
+        if (strcmp($attributeType, $comparisonValueType) !== 0) {
+            throw new FilterException(
+                "\"ge\" filter operator requires the attribute and the comparison value to be of the same type"
+            );
+        }
+
+        switch ($attributeType) {
+            case "string":
+                // Try to parse string to date to see if we need to compare timestamps
+                if (
+                    strtotime($attribute) !== false
+                    && strtotime($comparisonValue) !== false
+                ) {
+                    if (strtotime($attribute) >= strtotime($comparisonValue)) {
+                        return true;
+                    }
+                } else { // If not date, but just regular string, then perform lexicographic comparison
+                    if (strcasecmp($attribute, $comparisonValue) >= 0) {
+                        return true;
+                    }
+                }
+                break;
+
+            case "integer":
+                if ($attribute >= $comparisonValue) {
+                    return true;
+                }
+                break;
+
+            // For any other data type, throw an exception
+            // TODO: Return 400 with "scimType" of "invalidFilter" as per
+            // https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+            default:
+                throw new FilterException("Unsupported type for \"ge\" operation");
+                break;
+        }
+
+        return false;
+    }
+
+    private static function lessThanFilter($attribute, $comparisonValue)
+    {
+        $comparisonValueType = gettype($comparisonValue);
+
+        $attributeType = gettype($attribute);
+
+        // First, make sure that the attribute and the comparison value have the same type
+        if (strcmp($attributeType, $comparisonValueType) !== 0) {
+            throw new FilterException(
+                "\"lt\" filter operator requires the attribute and the comparison value to be of the same type"
+            );
+        }
+
+        switch ($attributeType) {
+            case "string":
+                // Try to parse string to date to see if we need to compare timestamps
+                if (
+                    strtotime($attribute) !== false
+                    && strtotime($comparisonValue) !== false
+                ) {
+                    if (strtotime($attribute) < strtotime($comparisonValue)) {
+                        return true;
+                    }
+                } else { // If not date, but just regular string, then perform lexicographic comparison
+                    if (strcasecmp($attribute, $comparisonValue) < 0) {
+                        return true;
+                    }
+                }
+                break;
+
+            case "integer":
+                if ($attribute < $comparisonValue) {
+                    return true;
+                }
+                break;
+
+            // For any other data type, throw an exception
+            // TODO: Return 400 with "scimType" of "invalidFilter" as per
+            // https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+            default:
+                throw new FilterException("Unsupported type for \"lt\" operation");
+                break;
+        }
+
+        return false;
+    }
+
+    private static function lessThanOrEqualToFilter($attribute, $comparisonValue)
+    {
+        $comparisonValueType = gettype($comparisonValue);
+
+        $attributeType = gettype($attribute);
+
+        // First, make sure that the attribute and the comparison value have the same type
+        if (strcmp($attributeType, $comparisonValueType) !== 0) {
+            throw new FilterException(
+                "\"le\" filter operator requires the attribute and the comparison value to be of the same type"
+            );
+        }
+
+        switch ($attributeType) {
+            case "string":
+                // Try to parse string to date to see if we need to compare timestamps
+                if (
+                    strtotime($attribute) !== false
+                    && strtotime($comparisonValue) !== false
+                ) {
+                    if (strtotime($attribute) <= strtotime($comparisonValue)) {
+                        return true;
+                    }
+                } else { // If not date, but just regular string, then perform lexicographic comparison
+                    if (strcasecmp($attribute, $comparisonValue) <= 0) {
+                        return true;
+                    }
+                }
+                break;
+
+            case "integer":
+                if ($attribute <= $comparisonValue) {
+                    return true;
+                }
+                break;
+
+            // For any other data type, throw an exception
+            // TODO: Return 400 with "scimType" of "invalidFilter" as per
+            // https://www.rfc-editor.org/rfc/rfc7644.html#section-3.4.2.2
+            default:
+                throw new FilterException("Unsupported type for \"le\" operation");
+                break;
+        }
+
+        return false;
+    }
+}
diff --git a/src/Util/Util.php b/src/Util/Util.php
index b5b0d0e..7df6663 100644
--- a/src/Util/Util.php
+++ b/src/Util/Util.php
@@ -2,11 +2,20 @@
 
 namespace Opf\Util;
 
+use Opf\Models\SCIM\Standard\Service\CoreResourceType;
+use Opf\Models\SCIM\Standard\Service\CoreSchemaExtension;
+use Exception;
+use PDO;
+
 abstract class Util
 {
+    private static string $defaultConfigFilePath = __DIR__ . '/../../config/config.default.php';
+    private static string $customConfigFilePath;
+
     public const USER_SCHEMA = "urn:ietf:params:scim:schemas:core:2.0:User";
     public const ENTERPRISE_USER_SCHEMA = "urn:ietf:params:scim:schemas:extension:enterprise:2.0:User";
-    public const PROVISIONING_USER_SCHEMA = "urn:audriga:params:scim:schemas:extension:provisioning:2.0:User";
+    public const PROVISIONING_USER_SCHEMA = "urn:ietf:params:scim:schemas:extension:audriga:provisioning:2.0:User";
+    public const DOMAIN_SCHEMA = "urn:ietf:params:scim:schemas:audriga:2.0:Domain";
     public const GROUP_SCHEMA = "urn:ietf:params:scim:schemas:core:2.0:Group";
     public const RESOURCE_TYPE_SCHEMA = "urn:ietf:params:scim:schemas:core:2.0:ResourceType";
     public const SERVICE_PROVIDER_CONFIGURATION_SCHEMA = "urn:ietf:params:scim:schemas:core:2.0:ServiceProviderConfig";
@@ -104,12 +113,20 @@ abstract class Util
                     isset($config['db']['driver']) && !empty($config['db']['driver'])
                     && isset($config['db']['host']) && !empty($config['db']['host'])
                     && isset($config['db']['port']) && !empty($config['db']['port'])
-                    && isset($config['db']['database']) && !empty($config['db']['database'])
+                    && isset($config['db']['database']) && !empty($config['db']['database']
+                    && strcmp($config['db']['driver'], 'mysql') === 0)
                 ) {
                     return $config['db']['driver'] . ':host='
                          . $config['db']['host'] . ';port='
                          . $config['db']['port'] . ';dbname='
                          . $config['db']['database'];
+                } elseif (
+                    isset($config['db']['driver']) && !empty($config['db']['driver'])
+                    && isset($config['db']['databaseFile']) && !empty($config['db']['databaseFile']
+                    && strcmp($config['db']['driver'], 'sqlite') === 0)
+                ) {
+                    return $config['db']['driver'] . ':host='
+                        . '../../' . $config['db']['databaseFile'];
                 }
             }
         }
@@ -119,6 +136,55 @@ abstract class Util
         return null;
     }
 
+    /**
+     * Utility method for providing a DB connection via PDO
+     *
+     * @throws Exception if there was an issue with obtaining the DB connection
+     * @return PDO A PDO object representing the DB connection
+     */
+    public static function getDbConnection()
+    {
+        // Try to obtain a DSN and complain with an Exception if there's no DSN
+        $dsn = self::buildDbDsn();
+        if (!isset($dsn)) {
+            throw new Exception("Can't obtain DSN to connect to DB");
+        }
+
+        $config = self::getConfigFile();
+        if (isset($config) && !empty($config)) {
+            if (isset($config['db']) && !empty($config['db'])) {
+                if (
+                    isset($config['db']['user'])
+                    && !empty($config['db']['user'])
+                    && isset($config['db']['password'])
+                    && !empty($config['db']['password'])
+                ) {
+                    $dbUsername = $config['db']['user'];
+                    $dbPassword = $config['db']['password'];
+                } else {
+                    // If no DB username and/or password provided, throw an Exception
+                    throw new Exception("No DB username and/or password provided to connect to DB");
+                }
+            }
+        }
+
+        // Create the DB connection with PDO
+        try {
+            $dbConnection = new PDO($dsn, $dbUsername, $dbPassword);
+        } catch (Exception $e) {
+            throw $e;
+        }
+
+        // Tell PDO explicitly to throw exceptions on errors, so as to have more info when debugging DB operations
+        if (isset($config['isInProduction'])) {
+            if ($config['isInProduction'] === false) {
+                $dbConnection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
+            }
+        }
+
+        return $dbConnection;
+    }
+
     public static function getDomainFromEmail($email)
     {
         $parts = explode("@", $email);
@@ -146,18 +212,147 @@ abstract class Util
      */
     public static function getConfigFile()
     {
-        $defaultConfigFilePath = dirname(__DIR__) . '/../config/config.default.php';
-        $customConfigFilePath = dirname(__DIR__) . '/../config/config.php';
-
         $config = [];
 
         // In case we don't have a custom config, we just rely on the default one
-        if (!file_exists($customConfigFilePath)) {
-            $config = require($defaultConfigFilePath);
+        if (!file_exists(self::$customConfigFilePath)) {
+            $config = require(self::$defaultConfigFilePath);
         } else {
-            $config = require($customConfigFilePath);
+            $config = require(self::$customConfigFilePath);
         }
 
         return $config;
     }
+
+    public static function setConfigFile(string $configFilePath)
+    {
+        self::$customConfigFilePath = $configFilePath;
+    }
+
+    /**
+     * A utility method for obtaining the supported SCIM resource types
+     *
+     * @param string $baseUrl A base URL required for each resource type that is returned
+     *
+     * @return array The array containing the resource types
+     */
+    public static function getResourceTypes($baseUrl)
+    {
+        // Check which resource types are supported via the config file and in this method further down below
+        // make sure to only return those that are indeed supported
+        $config = Util::getConfigFile();
+        $supportedResourceTypes = $config['supportedResourceTypes'];
+
+        $scimResourceTypes = [];
+
+        if (in_array('User', $supportedResourceTypes)) {
+            $userResourceType = new CoreResourceType();
+            $userResourceType->setId("User");
+            $userResourceType->setName("User");
+            $userResourceType->setEndpoint("/Users");
+            $userResourceType->setDescription("User Account");
+            $userResourceType->setSchema(Util::USER_SCHEMA);
+
+            if (in_array('EnterpriseUser', $supportedResourceTypes)) {
+                $enterpriseUserSchemaExtension = new CoreSchemaExtension();
+                $enterpriseUserSchemaExtension->setSchema(Util::ENTERPRISE_USER_SCHEMA);
+                $enterpriseUserSchemaExtension->setRequired(true);
+
+                $userResourceType->setSchemaExtensions(array($enterpriseUserSchemaExtension));
+            }
+            if (in_array('ProvisioningUser', $supportedResourceTypes)) {
+                $provisioningUserSchemaExtension = new CoreSchemaExtension();
+                $provisioningUserSchemaExtension->setSchema(Util::PROVISIONING_USER_SCHEMA);
+                $provisioningUserSchemaExtension->setRequired(true);
+
+                $userResourceType->setSchemaExtensions(array($provisioningUserSchemaExtension));
+            }
+
+            $scimResourceTypes[] = $userResourceType->toSCIM(false, $baseUrl);
+        }
+
+        if (in_array('Group', $supportedResourceTypes)) {
+            $groupResourceType = new CoreResourceType();
+            $groupResourceType->setId("Group");
+            $groupResourceType->setName("Group");
+            $groupResourceType->setEndpoint("/Groups");
+            $groupResourceType->setDescription("Group");
+            $groupResourceType->setSchema("urn:ietf:params:scim:schemas:core:2.0:Group");
+            $groupResourceType->setSchemaExtensions([]);
+
+            $scimResourceTypes[] = $groupResourceType->toSCIM(false, $baseUrl);
+        }
+
+        if (in_array('Domain', $supportedResourceTypes)) {
+            $domainResourceType = new CoreResourceType();
+            $domainResourceType->setId("Domain");
+            $domainResourceType->setName("Domain");
+            $domainResourceType->setEndpoint("/Domains");
+            $domainResourceType->setDescription("Domain");
+            $domainResourceType->setSchema(self::DOMAIN_SCHEMA);
+            $domainResourceType->setSchemaExtensions([]);
+
+            $scimResourceTypes[] = $domainResourceType->toSCIM(false, $baseUrl);
+        }
+
+        return $scimResourceTypes;
+    }
+
+    /**
+     * A utility method for obtaining the configured SCIM schemas
+     *
+     * @return array|null Return an array of schemas or null if no schemas were found
+     */
+    public static function getSchemas()
+    {
+        $config = Util::getConfigFile();
+        $supportedSchemas = $config['supportedResourceTypes'];
+        $mandatorySchemas = ['Schema', 'ResourceType'];
+
+        $scimSchemas = [];
+
+        // We store the schemas that the SCIM server supports in separate JSON files
+        // That's why we try to read them here and add them to $scimSchemas, which is returned as a result
+        $pathToSchemasDir = dirname(__DIR__, 2) . '/config/Schema';
+        $schemaFiles = scandir($pathToSchemasDir, SCANDIR_SORT_NONE);
+
+        // If scandir() failed (i.e., it returned false), then return null
+        if ($schemaFiles === false) {
+            return null;
+        }
+
+        foreach ($schemaFiles as $schemaFile) {
+            if (!in_array($schemaFile, array('.', '..'))) {
+                $scimSchemaJsonDecoded = json_decode(file_get_contents($pathToSchemasDir . '/' . $schemaFile), true);
+
+                // Only return schemas that are either mandatory (like the 'Schema' and 'ResourceType' ones)
+                // or supported by the server
+                if (in_array($scimSchemaJsonDecoded['name'], array_merge($supportedSchemas, $mandatorySchemas))) {
+                    $scimSchemas[] = $scimSchemaJsonDecoded;
+                }
+            }
+        }
+
+        return $scimSchemas;
+    }
+
+    /**
+     * A utility method for obtaining the SCIM service provider configuration
+     *
+     * @return string|null Return the service provider configuration or null if no config was found
+     */
+    public static function getServiceProviderConfig()
+    {
+        $pathToServiceProviderConfigurationFile =
+            dirname(__DIR__, 2) . '/config/ServiceProviderConfig/serviceProviderConfig.json';
+
+        $scimServiceProviderConfigurationFile = file_get_contents($pathToServiceProviderConfigurationFile);
+
+        // If there was no service provider config JSON file found, then return null
+        if ($scimServiceProviderConfigurationFile === false) {
+            return null;
+        }
+
+        return $scimServiceProviderConfigurationFile;
+    }
 }
diff --git a/src/eloquent.php b/src/eloquent.php
deleted file mode 100644
index 41088d4..0000000
--- a/src/eloquent.php
+++ /dev/null
@@ -1,15 +0,0 @@
-<?php
-
-use Opf\Util\Util;
-use Slim\App;
-
-return static function (App $app) {
-    $config = Util::getConfigFile();
-    $dbSettings = $config['db'];
-
-    // Boot eloquent
-    $capsule = new Illuminate\Database\Capsule\Manager();
-    $capsule->addConnection($dbSettings);
-    $capsule->setAsGlobal();
-    $capsule->bootEloquent();
-};
diff --git a/src/routes.php b/src/routes.php
index cb62e1c..b98f6f8 100644
--- a/src/routes.php
+++ b/src/routes.php
@@ -1,11 +1,15 @@
 <?php
 
+use Opf\Controllers\Domains\CreateDomainAction;
+use Opf\Controllers\Domains\DeleteDomainAction;
+use Opf\Controllers\Domains\GetDomainAction;
+use Opf\Controllers\Domains\ListDomainsAction;
+use Opf\Controllers\Domains\UpdateDomainAction;
 use Opf\Controllers\Groups\CreateGroupAction;
 use Opf\Controllers\Groups\DeleteGroupAction;
 use Opf\Controllers\Groups\GetGroupAction;
 use Opf\Controllers\Groups\ListGroupsAction;
 use Opf\Controllers\Groups\UpdateGroupAction;
-use Opf\Controllers\JWT\GenerateJWTAction;
 use Opf\Controllers\ServiceProviders\ListResourceTypesAction;
 use Opf\Controllers\ServiceProviders\ListSchemasAction;
 use Opf\Controllers\ServiceProviders\ListServiceProviderConfigurationsAction;
@@ -41,6 +45,14 @@ return function (App $app) {
         $app->delete('/Groups/{id}', DeleteGroupAction::class)->setName('groups.delete');
     }
 
+    if (in_array('Domain', $supportedResourceTypes)) {
+        $app->get('/Domains', ListDomainsAction::class)->setName('domains.list');
+        $app->get('/Domains/{id}', GetDomainAction::class)->setName('domains.get');
+        $app->post('/Domains', CreateDomainAction::class)->setName('domains.create');
+        $app->put('/Domains/{id}', UpdateDomainAction::class)->setName('domains.update');
+        $app->delete('/Domains/{id}', DeleteDomainAction::class)->setName('domains.delete');
+    }
+
     // ServiceProvider routes
     $app->get('/ResourceTypes', ListResourceTypesAction::class)->setName('resourceTypes.list');
     $app->get('/Schemas', ListSchemasAction::class)->setName('schemas.list');
@@ -48,7 +60,4 @@ return function (App $app) {
         '/ServiceProviderConfig',
         ListServiceProviderConfigurationsAction::class
     )->setName('serviceProviderConfigs.list');
-
-    // JWT
-    $app->get('/jwt', GenerateJWTAction::class)->setName('jwt.generate');
 };
diff --git a/test/postman/scim-env.postman_environment.json b/test/postman/scim-env.postman_environment.json
index 17d0511..849922d 100644
--- a/test/postman/scim-env.postman_environment.json
+++ b/test/postman/scim-env.postman_environment.json
@@ -1,5 +1,5 @@
 {
-	"id": "7880a4e5-d9ce-42f8-8ed0-57f886616527",
+	"id": "938b836a-076e-4938-a04a-3f088c363ff0",
 	"name": "scim-env",
 	"values": [
 		{
@@ -7,9 +7,21 @@
 			"value": "http://localhost:8888",
 			"type": "default",
 			"enabled": true
+		},
+		{
+			"key": "superadmin_jwt",
+			"value": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyIjoiYWRtaW5AbG9jYWxob3N0Lm9yZyJ9.z5j4P09bk7StVda48g9_0Jt0LhopiNhjmmeguQCrVx8",
+			"type": "any",
+			"enabled": true
+		},
+		{
+			"key": "non_superadmin_jwt",
+			"value": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyIjoidGVzdEB0ZXN0Lm9yZyJ9.Lu1JcCSUiTRPGeuLgs6k6TG5DgCpuAIyA8IKg_nli5M",
+			"type": "default",
+			"enabled": true
 		}
 	],
 	"_postman_variable_scope": "environment",
-	"_postman_exported_at": "2022-04-14T14:54:36.929Z",
-	"_postman_exported_using": "Postman/9.15.2"
-}
\ No newline at end of file
+	"_postman_exported_at": "2022-10-07T10:05:35.659Z",
+	"_postman_exported_using": "Postman/9.31.0"
+}
diff --git a/test/postman/scim-opf-pfa.postman_collection.json b/test/postman/scim-opf-pfa.postman_collection.json
deleted file mode 100644
index 9f3a833..0000000
--- a/test/postman/scim-opf-pfa.postman_collection.json
+++ /dev/null
@@ -1,597 +0,0 @@
-{
-	"info": {
-		"_postman_id": "2b79327d-70c4-425f-942f-6037f38d67e5",
-		"name": "PFA SCIM PHP Collection",
-		"schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json"
-	},
-	"item": [
-		{
-			"name": "JWT",
-			"item": [
-				{
-					"name": "Get JWT",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"const response = pm.response.json();",
-									"pm.environment.set(\"jwt_token\", response.Bearer)"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [],
-						"url": {
-							"raw": "{{url}}/jwt",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"jwt"
-							]
-						}
-					},
-					"response": []
-				}
-			]
-		},
-		{
-			"name": "ResourceTypes",
-			"item": [
-				{
-					"name": "Read all ResourceTypes",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 200\", () => {",
-									"    pm.response.to.have.status(200);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json().Resources).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains exactly one entry\", () => {",
-									"    pm.expect(pm.response.json().Resources.length).to.eql(1);",
-									"});",
-									"",
-									"pm.test(\"Response body contains ResourceType with id \\\"User\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[0].id).to.eql(\"User\");",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/ResourceTypes",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"ResourceTypes"
-							]
-						}
-					},
-					"response": []
-				}
-			]
-		},
-		{
-			"name": "Schemas",
-			"item": [
-				{
-					"name": "Read all Schemas",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 200\", () => {",
-									"    pm.response.to.have.status(200);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json().Resources).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains exactly four entries\", () => {",
-									"    pm.expect(pm.response.json().Resources.length).to.eql(4);",
-									"});",
-									"",
-									"pm.test(\"Response body contains Schema with id \\\"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[0].id).to.eql(\"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:ResourceType\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[1].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:ResourceType\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:User\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[2].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:User\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:Schema\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[3].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:Schema\");",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/Schemas",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Schemas"
-							]
-						}
-					},
-					"response": []
-				}
-			]
-		},
-		{
-			"name": "ServiceProviderConfigs",
-			"item": [
-				{
-					"name": "Read all ServiceProviderConfigs",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 200\", () => {",
-									"    pm.response.to.have.status(200);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json()).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains a ServiceProviderConfig with a correct schema\", () => {",
-									"    pm.expect(pm.response.json().schemas).to.include(\"urn:ietf:params:scim:schemas:core:2.0:ServiceProviderConfig\");",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/ServiceProviderConfig",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"ServiceProviderConfig"
-							]
-						}
-					},
-					"response": []
-				}
-			]
-		},
-		{
-			"name": "Users",
-			"item": [
-				{
-					"name": "Create a single user",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 201\", () => {",
-									"    pm.response.to.have.status(201);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json()).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with userName \\\"createdtestuser@test.org\\\"\", () => {",
-									"    pm.expect(pm.response.json().userName).to.eql(\"createdtestuser@test.org\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains a valid non-null user ID (the ID of the user which was created)\", () => {",
-									"    pm.expect(pm.response.json().id).to.not.be.null;",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with sizeQuota equal to 12345\", () => {",
-									"    pm.expect(pm.response.json()[\"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\"].sizeQuota).to.eql(12345);",
-									"});",
-									"",
-									"pm.collectionVariables.set(\"testUserId\", pm.response.json().id);"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "POST",
-						"header": [
-							{
-								"key": "Content-Type",
-								"value": "application/scim+json",
-								"type": "default"
-							}
-						],
-						"body": {
-							"mode": "raw",
-							"raw": "{\n    \"userName\": \"createdtestuser@test.org\",\n    \"id\": \"createdtestuser@test.org\",\n    \"active\": true,\n    \"password\": \"somepass123\",\n    \"displayName\": \"createdtestuser\",\n    \"emails\": [{\"value\":\"createdtestuser@test.org\"}],\n    \"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\": {\n        \"sizeQuota\": 12345\n    }\n}",
-							"options": {
-								"raw": {
-									"language": "json"
-								}
-							}
-						},
-						"url": {
-							"raw": "{{url}}/Users",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Users"
-							]
-						}
-					},
-					"response": []
-				},
-				{
-					"name": "Read a single user",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 200\", () => {",
-									"    pm.response.to.have.status(200);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json()).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains the user ID of the user we want to read\", () => {",
-									"    pm.expect(pm.response.json().id).to.eql(\"createdtestuser@test.org\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with userName \\\"createdtestuser@test.org\\\"\", () => {",
-									"    pm.expect(pm.response.json().userName).to.eql(\"createdtestuser@test.org\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with sizeQuota equal to 12345\", () => {",
-									"    pm.expect(pm.response.json()[\"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\"].sizeQuota).to.eql(12345);",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/Users/{{testUserId}}",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Users",
-								"{{testUserId}}"
-							]
-						}
-					},
-					"response": []
-				},
-				{
-					"name": "Read a non-existent user",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 404\", () => {",
-									"    pm.response.to.have.status(404);",
-									"});",
-									"",
-									"pm.test(\"Response body is empty\", () => {",
-									"    pm.expect(pm.response.body).to.be.undefined;",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/Users/some-non-existent-user@test.org",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Users",
-								"some-non-existent-user@test.org"
-							]
-						}
-					},
-					"response": []
-				},
-				{
-					"name": "Read all users",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 200\", () => {",
-									"    pm.response.to.have.status(200);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json().Resources).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with userName \\\"createdtestuser@test.org\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[0].userName).to.eql(\"createdtestuser@test.org\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with sizeQuota equal to 12345\", () => {",
-									"    pm.expect(pm.response.json().Resources[0][\"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\"].sizeQuota).to.eql(12345);",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "GET",
-						"header": [
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/Users",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Users"
-							]
-						}
-					},
-					"response": []
-				},
-				{
-					"name": "Update a single user",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 200\", () => {",
-									"    pm.response.to.have.status(200);",
-									"});",
-									"",
-									"pm.test(\"Content-Type header is application/scim+json\", () => {",
-									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
-									"});",
-									"",
-									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json()).to.not.be.empty;",
-									"});",
-									"",
-									"pm.test(\"Response body contains the user ID of the user we want to read\", () => {",
-									"    pm.expect(pm.response.json().id).to.eql(pm.collectionVariables.get('testUserId'));",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with displayName \\\"updatedtestuser\\\"\", () => {",
-									"    pm.expect(pm.response.json().displayName).to.eql(\"updatedtestuser\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains user with sizeQuota equal to 123456789\", () => {",
-									"    pm.expect(pm.response.json()[\"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\"].sizeQuota).to.eql(123456789);",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "PUT",
-						"header": [
-							{
-								"key": "Content-Type",
-								"value": "application/scim+json",
-								"type": "default"
-							},
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"body": {
-							"mode": "raw",
-							"raw": "{\n    \"id\": \"createdtestuser@test.org\",\n    \"displayName\": \"updatedtestuser\",\n    \"urn:audriga:params:scim:schemas:extension:provisioning:2.0:User\": {\n        \"sizeQuota\": 123456789\n    }\n}",
-							"options": {
-								"raw": {
-									"language": "json"
-								}
-							}
-						},
-						"url": {
-							"raw": "{{url}}/Users/{{testUserId}}",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Users",
-								"{{testUserId}}"
-							]
-						}
-					},
-					"response": []
-				},
-				{
-					"name": "Delete a single user",
-					"event": [
-						{
-							"listen": "test",
-							"script": {
-								"exec": [
-									"pm.test(\"Response status code is 204\", () => {",
-									"    pm.response.to.have.status(204);",
-									"});"
-								],
-								"type": "text/javascript"
-							}
-						}
-					],
-					"request": {
-						"method": "DELETE",
-						"header": [
-							{
-								"key": "Content-Type",
-								"value": "application/scim+json",
-								"type": "default"
-							},
-							{
-								"key": "Authorization",
-								"value": "Bearer: {{jwt_token}}",
-								"type": "default"
-							}
-						],
-						"url": {
-							"raw": "{{url}}/Users/{{testUserId}}",
-							"host": [
-								"{{url}}"
-							],
-							"path": [
-								"Users",
-								"{{testUserId}}"
-							]
-						}
-					},
-					"response": []
-				}
-			]
-		}
-	],
-	"auth": {
-		"type": "bearer",
-		"bearer": [
-			{
-				"key": "token",
-				"value": "{{jwt_token}}",
-				"type": "string"
-			}
-		]
-	},
-	"event": [
-		{
-			"listen": "prerequest",
-			"script": {
-				"type": "text/javascript",
-				"exec": [
-					""
-				]
-			}
-		},
-		{
-			"listen": "test",
-			"script": {
-				"type": "text/javascript",
-				"exec": [
-					""
-				]
-			}
-		}
-	],
-	"variable": [
-		{
-			"key": "testUserId",
-			"value": ""
-		},
-		{
-			"key": "testGroupId",
-			"value": ""
-		}
-	]
-}
\ No newline at end of file
diff --git a/test/postman/scim-opf.postman_collection.json b/test/postman/scim-opf.postman_collection.json
index 0d2bcd9..94861b1 100644
--- a/test/postman/scim-opf.postman_collection.json
+++ b/test/postman/scim-opf.postman_collection.json
@@ -1,10 +1,44 @@
 {
 	"info": {
-		"_postman_id": "73043646-f766-4adc-96ee-05316cc59bdd",
+		"_postman_id": "c90f5107-b2fb-46dc-9a32-b07f5ff68440",
 		"name": "SCIM PHP Collection",
 		"schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json"
 	},
 	"item": [
+		{
+			"name": "JWT",
+			"item": [
+				{
+					"name": "Get JWT",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"const response = pm.response.json();",
+									"pm.environment.set(\"jwt_token\", response.Bearer)"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/jwt",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"jwt"
+							]
+						}
+					},
+					"response": []
+				}
+			]
+		},
 		{
 			"name": "Users",
 			"item": [
@@ -138,7 +172,8 @@
 									"});",
 									"",
 									"pm.test(\"Response body contains user with userName \\\"createdtestuser\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[0].userName).to.eql(\"createdtestuser\");",
+									"    var resources = pm.response.json().Resources.map(x => x.userName);",
+									"    pm.expect(resources).to.contain(\"createdtestuser\");",
 									"});"
 								],
 								"type": "text/javascript"
@@ -160,6 +195,154 @@
 					},
 					"response": []
 				},
+				{
+					"name": "Filter users by userName",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"pm.test(\"Response status code is 200\", () => {",
+									"    pm.response.to.have.status(200);",
+									"});",
+									"",
+									"pm.test(\"Content-Type header is application/scim+json\", () => {",
+									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
+									"});",
+									"",
+									"pm.test(\"Response body is not empty\", () => {",
+									"    pm.expect(pm.response.json()).to.not.be.empty;",
+									"});",
+									"",
+									"pm.test(\"Response body contains user with userName \\\"createdtestuser\\\"\", () => {",
+									"    pm.expect(pm.response.json().Resources[0].userName).to.eql(\"createdtestuser\");",
+									"});",
+									"",
+									"pm.test(\"Response body contains a valid non-null user ID\", () => {",
+									"    pm.expect(pm.response.json().id).to.not.be.null;",
+									"});"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/Users?filter=userName%20eq%20createdtestuser",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"Users"
+							],
+							"query": [
+								{
+									"key": "filter",
+									"value": "userName%20eq%20createdtestuser"
+								}
+							]
+						}
+					},
+					"response": []
+				},
+				{
+					"name": "Filter users with invalid filter",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"pm.test(\"Response status code is 500\", () => {",
+									"    pm.response.to.have.status(500);",
+									"});",
+									"",
+									"pm.test(\"Content-Type header is application/scim+json\", () => {",
+									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
+									"});",
+									"",
+									"pm.test(\"Response body is not empty\", () => {",
+									"    pm.expect(pm.response.json()).to.not.be.empty;",
+									"});",
+									"",
+									"pm.test(\"Response body contains error '\\\"pr\\\" filter operator must be used without a comparison value'\", () => {",
+									"    pm.expect(pm.response.json().error.description).to.eql(\"\\\"pr\\\" filter operator must be used without a comparison value\");",
+									"});"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/Users?filter=userName%20pr%20createdtestuser",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"Users"
+							],
+							"query": [
+								{
+									"key": "filter",
+									"value": "userName%20pr%20createdtestuser"
+								}
+							]
+						}
+					},
+					"response": []
+				},
+				{
+					"name": "Filter users with unmatching filter",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"pm.test(\"Response status code is 200\", () => {",
+									"    pm.response.to.have.status(200);",
+									"});",
+									"",
+									"pm.test(\"Content-Type header is application/scim+json\", () => {",
+									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
+									"});",
+									"",
+									"pm.test(\"Response body is not empty\", () => {",
+									"    pm.expect(pm.response.json()).to.not.be.empty;",
+									"});",
+									"",
+									"pm.test(\"Response body contains no users\", () => {",
+									"    pm.expect(pm.response.json().Resources).to.be.empty;",
+									"});"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/Users?filter=userName%20sw%20somenonexistentstring",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"Users"
+							],
+							"query": [
+								{
+									"key": "filter",
+									"value": "userName%20sw%20somenonexistentstring"
+								}
+							]
+						}
+					},
+					"response": []
+				},
 				{
 					"name": "Update a single user",
 					"event": [
@@ -403,7 +586,8 @@
 									"});",
 									"",
 									"pm.test(\"Response body contains group with displayName \\\"createdtestgroup\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[0].displayName).to.eql(\"createdtestgroup\");",
+									"    var resources = pm.response.json().Resources.map(x => x.displayName);",
+									"    pm.expect(resources).to.contain(\"createdtestgroup\");",
 									"});"
 								],
 								"type": "text/javascript"
@@ -425,6 +609,154 @@
 					},
 					"response": []
 				},
+				{
+					"name": "Filter groups by displayName",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"pm.test(\"Response status code is 200\", () => {",
+									"    pm.response.to.have.status(200);",
+									"});",
+									"",
+									"pm.test(\"Content-Type header is application/scim+json\", () => {",
+									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
+									"});",
+									"",
+									"pm.test(\"Response body is not empty\", () => {",
+									"    pm.expect(pm.response.json()).to.not.be.empty;",
+									"});",
+									"",
+									"pm.test(\"Response body contains group with displayName \\\"createdtestgroup\\\"\", () => {",
+									"    pm.expect(pm.response.json().Resources[0].displayName).to.eql(\"createdtestgroup\");",
+									"});",
+									"",
+									"pm.test(\"Response body contains a valid non-null group ID\", () => {",
+									"    pm.expect(pm.response.json().id).to.not.be.null;",
+									"});"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/Groups?filter=displayName%20eq%20createdtestgroup",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"Groups"
+							],
+							"query": [
+								{
+									"key": "filter",
+									"value": "displayName%20eq%20createdtestgroup"
+								}
+							]
+						}
+					},
+					"response": []
+				},
+				{
+					"name": "Filter groups with invalid filter",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"pm.test(\"Response status code is 500\", () => {",
+									"    pm.response.to.have.status(500);",
+									"});",
+									"",
+									"pm.test(\"Content-Type header is application/scim+json\", () => {",
+									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
+									"});",
+									"",
+									"pm.test(\"Response body is not empty\", () => {",
+									"    pm.expect(pm.response.json()).to.not.be.empty;",
+									"});",
+									"",
+									"pm.test(\"Response body contains error '\\\"pr\\\" filter operator must be used without a comparison value'\", () => {",
+									"    pm.expect(pm.response.json().error.description).to.eql(\"\\\"pr\\\" filter operator must be used without a comparison value\");",
+									"});"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/Groups?filter=displayName%20pr%20createdtestgroup",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"Groups"
+							],
+							"query": [
+								{
+									"key": "filter",
+									"value": "displayName%20pr%20createdtestgroup"
+								}
+							]
+						}
+					},
+					"response": []
+				},
+				{
+					"name": "Filter groups with unmatching filter",
+					"event": [
+						{
+							"listen": "test",
+							"script": {
+								"exec": [
+									"pm.test(\"Response status code is 200\", () => {",
+									"    pm.response.to.have.status(200);",
+									"});",
+									"",
+									"pm.test(\"Content-Type header is application/scim+json\", () => {",
+									"    pm.expect(pm.response.headers.get('Content-Type')).to.eql('application/scim+json');",
+									"});",
+									"",
+									"pm.test(\"Response body is not empty\", () => {",
+									"    pm.expect(pm.response.json()).to.not.be.empty;",
+									"});",
+									"",
+									"pm.test(\"Response body contains no groups\", () => {",
+									"    pm.expect(pm.response.json().Resources).to.be.empty;",
+									"});"
+								],
+								"type": "text/javascript"
+							}
+						}
+					],
+					"request": {
+						"method": "GET",
+						"header": [],
+						"url": {
+							"raw": "{{url}}/Groups?filter=displayName%20sw%20somenonexistentstring",
+							"host": [
+								"{{url}}"
+							],
+							"path": [
+								"Groups"
+							],
+							"query": [
+								{
+									"key": "filter",
+									"value": "displayName%20sw%20somenonexistentstring"
+								}
+							]
+						}
+					},
+					"response": []
+				},
 				{
 					"name": "Update a single group",
 					"event": [
@@ -579,6 +911,8 @@
 							"listen": "test",
 							"script": {
 								"exec": [
+									"jsonData = pm.response.json();",
+									"",
 									"pm.test(\"Response status code is 200\", () => {",
 									"    pm.response.to.have.status(200);",
 									"});",
@@ -588,31 +922,30 @@
 									"});",
 									"",
 									"pm.test(\"Response body is not empty\", () => {",
-									"    pm.expect(pm.response.json().Resources).to.not.be.empty;",
+									"    pm.expect(jsonData.Resources).to.not.be.empty;",
 									"});",
 									"",
-									"pm.test(\"Response body contains exactly five entries\", () => {",
-									"    pm.expect(pm.response.json().Resources.length).to.eql(5);",
+									"pm.test(\"Response body contains exactly four entries\", () => {",
+									"    pm.expect(jsonData.Resources.length).to.eql(4);",
 									"});",
 									"",
 									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:Group\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[0].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:Group\");",
+									"    isContained = jsonData.Resources.some((resource) => resource.id === \"urn:ietf:params:scim:schemas:core:2.0:Group\");",
+									"    pm.expect(isContained).to.be.true;",
 									"});",
 									"",
 									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:ResourceType\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[1].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:ResourceType\");",
+									"    isContained = jsonData.Resources.some((resource) => resource.id === \"urn:ietf:params:scim:schemas:core:2.0:ResourceType\");",
+									"    pm.expect(isContained).to.be.true;",
 									"});",
 									"",
 									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:Schema\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[2].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:Schema\");",
+									"    isContained = jsonData.Resources.some((resource) => resource.id === \"urn:ietf:params:scim:schemas:core:2.0:Schema\");",
+									"    pm.expect(isContained).to.be.true;",
 									"});",
 									"",
 									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:core:2.0:User\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[3].id).to.eql(\"urn:ietf:params:scim:schemas:core:2.0:User\");",
-									"});",
-									"",
-									"pm.test(\"Response body contains Schema with id \\\"urn:ietf:params:scim:schemas:extension:enterprise:2.0:User\\\"\", () => {",
-									"    pm.expect(pm.response.json().Resources[4].id).to.eql(\"urn:ietf:params:scim:schemas:extension:enterprise:2.0:User\");",
+									"    isContained = jsonData.Resources.some((resource) => resource.id === \"urn:ietf:params:scim:schemas:core:2.0:User\");",
 									"});"
 								],
 								"type": "text/javascript"
@@ -684,6 +1017,16 @@
 			]
 		}
 	],
+	"auth": {
+		"type": "bearer",
+		"bearer": [
+			{
+				"key": "token",
+				"value": "{{jwt_token}}",
+				"type": "string"
+			}
+		]
+	},
 	"event": [
 		{
 			"listen": "prerequest",
diff --git a/test/resources/filterTestGroups.json b/test/resources/filterTestGroups.json
new file mode 100644
index 0000000..4988d3e
--- /dev/null
+++ b/test/resources/filterTestGroups.json
@@ -0,0 +1,17 @@
+[
+    {
+        "displayName": "testGroup",
+        "members": []
+    },
+    {
+        "displayName": "testGroup2",
+        "members": []
+    },
+    {
+        "displayName": "testGroup3",
+        "members": [
+            "12345678-9012-3456-7890-12345678",
+            "87654321-2109-6543-0987-87654321"
+        ]
+    }
+]
\ No newline at end of file
diff --git a/test/resources/filterTestUsers.json b/test/resources/filterTestUsers.json
new file mode 100644
index 0000000..659df83
--- /dev/null
+++ b/test/resources/filterTestUsers.json
@@ -0,0 +1,19 @@
+[
+    {
+        "userName": "testuser",
+        "profileUrl": "http://example.com/testuser"
+    },
+    {
+        "userName": "testuser2",
+        "externalId": "testuser2external",
+        "name": {
+            "givenName": "given",
+            "familyName": "family"
+        }
+    },
+    {
+        "userName": "testuser3",
+        "externalId": "testuser3external",
+        "profileUrl": "http://example.com/testuser3"
+    }
+]
\ No newline at end of file
diff --git a/test/resources/mock-test-config.php b/test/resources/mock-test-config.php
new file mode 100644
index 0000000..fdf4dcd
--- /dev/null
+++ b/test/resources/mock-test-config.php
@@ -0,0 +1,25 @@
+<?php
+
+return [
+    'isInProduction' => false, // Set to true when deploying in production
+    'basePath' => null, // If you want to specify a base path for the Slim app, add it here (e.g., '/test/scim')
+    'supportedResourceTypes' => ['User', 'Group'], // Specify all the supported SCIM ResourceTypes by their names here
+
+    // SQLite DB settings
+    'db' => [
+        'driver' => 'sqlite', // Type of DB
+        'databaseFile' => 'db/scim-mock.sqlite' // DB name
+    ],
+
+    // Monolog settings
+    'logger' => [
+        'name' => 'scim-opf',
+        'path' => isset($_ENV['docker']) ? 'php://stdout' : __DIR__ . '/../../logs/app.log',
+        'level' => \Monolog\Logger::DEBUG,
+    ],
+
+    // Bearer token settings
+    'jwt' => [
+        'secret' => 'secret'
+    ]
+];
diff --git a/test/unit/FilterParserTest.php b/test/unit/FilterParserTest.php
new file mode 100644
index 0000000..27b2d00
--- /dev/null
+++ b/test/unit/FilterParserTest.php
@@ -0,0 +1,57 @@
+<?php
+
+namespace Opf\Test\Unit;
+
+use Opf\Models\SCIM\Standard\Filters\AttributeExpression;
+use Opf\Models\SCIM\Standard\Filters\AttributeOperator;
+use Opf\Models\SCIM\Standard\Filters\FilterException;
+use Opf\Models\SCIM\Standard\Filters\FilterExpression;
+use Opf\Util\Filters\FilterParser;
+use PHPUnit\Framework\TestCase;
+
+final class FilterParserTest extends TestCase
+{
+    public function testParseAttributeFilterExpression()
+    {
+        // Test an "eq" filter expression
+        $filterString = "userName eq sometestusername";
+        $attributeFilterExpression = FilterParser::parseFilterExpression($filterString);
+
+        $this->assertInstanceOf(FilterExpression::class, $attributeFilterExpression);
+        $this->assertInstanceOf(AttributeExpression::class, $attributeFilterExpression);
+
+        $this->assertEquals("userName", $attributeFilterExpression->getAttributePath());
+        $this->assertEquals(AttributeOperator::OP_EQ, $attributeFilterExpression->getCompareOperator());
+        $this->assertEquals("sometestusername", $attributeFilterExpression->getComparisonValue());
+
+
+        // Test a "pr" filter expression
+        $filterString = "meta.created pr";
+        $attributeFilterExpression = FilterParser::parseFilterExpression($filterString);
+
+        $this->assertInstanceOf(FilterExpression::class, $attributeFilterExpression);
+        $this->assertInstanceOf(AttributeExpression::class, $attributeFilterExpression);
+
+        $this->assertEquals("meta.created", $attributeFilterExpression->getAttributePath());
+        $this->assertEquals(AttributeOperator::OP_PR, $attributeFilterExpression->getCompareOperator());
+        $this->assertNull($attributeFilterExpression->getComparisonValue());
+    }
+
+    public function testParseTooShortFilterExpression()
+    {
+        $this->expectException(FilterException::class);
+        $this->expectExceptionMessage("Incorrectly formatted AttributeExpression");
+
+        $filterString = "somestring";
+        $parsedFilterExpression = FilterParser::parseFilterExpression($filterString);
+    }
+
+    public function testParseTooLongFilterExpression()
+    {
+        $this->expectException(FilterException::class);
+        $this->expectExceptionMessage("Incorrectly formatted AttributeExpression");
+
+        $filterString = "userName eq some value";
+        $parsedFilterExpression = FilterParser::parseFilterExpression($filterString);
+    }
+}
diff --git a/test/unit/FilterUtilTest.php b/test/unit/FilterUtilTest.php
new file mode 100644
index 0000000..7b084b1
--- /dev/null
+++ b/test/unit/FilterUtilTest.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Opf\Test\Unit;
+
+use Opf\Models\SCIM\Standard\Filters\FilterException;
+use Opf\Util\Filters\FilterParser;
+use Opf\Util\Filters\FilterUtil;
+use PHPUnit\Framework\TestCase;
+
+final class FilterUtilTest extends TestCase
+{
+    /** @var array */
+    protected $scimGroups = [];
+
+    /** @var array */
+    protected $scimUsers = [];
+
+    public function setUp(): void
+    {
+        $this->scimGroups = json_decode(file_get_contents(__DIR__ . '/../resources/filterTestGroups.json'), true);
+        $this->scimUsers = json_decode(file_get_contents(__DIR__ . '/../resources/filterTestUsers.json'), true);
+    }
+
+    public function tearDown(): void
+    {
+        $this->scimGroups = [];
+        $this->scimUsers = [];
+    }
+
+    public function testGroupFiltering()
+    {
+        // "ne" filter test
+        $filterString = "displayName ne testGroup";
+        $filteredScimGroups = FilterUtil::performFiltering($filterString, $this->scimGroups);
+
+        $this->assertEquals(array_splice($this->scimGroups, 1, 2), $filteredScimGroups);
+    }
+
+    public function testUserFiltering()
+    {
+        // "sw" filter test
+        $filterString = "userName sw testuser";
+        $filteredScimUsers = FilterUtil::performFiltering($filterString, $this->scimUsers);
+
+        $this->assertEquals($this->scimUsers, $filteredScimUsers);
+    }
+
+    public function testInvalidFiltering()
+    {
+        $this->expectException(FilterException::class);
+        $this->expectExceptionMessage("Incorrectly formatted AttributeExpression");
+        
+        $filterString = "externalId eq some value";
+        $filteredScimUsers = FilterUtil::performFiltering($filterString, $this->scimUsers);
+    }
+}
diff --git a/test/unit/MockGroupsDataAccessTest.php b/test/unit/MockGroupsDataAccessTest.php
index 4097cbf..9828ba5 100644
--- a/test/unit/MockGroupsDataAccessTest.php
+++ b/test/unit/MockGroupsDataAccessTest.php
@@ -3,85 +3,50 @@
 namespace Opf\Test\Unit;
 
 use Illuminate\Database\Capsule\Manager;
+use Opf\Adapters\Groups\MockGroupAdapter;
 use Opf\DataAccess\Groups\MockGroupDataAccess;
+use Opf\Models\SCIM\Standard\Groups\CoreGroup;
+use Opf\Util\Util;
 use PHPUnit\Framework\TestCase;
 use SQLite3;
 
 final class MockGroupsDataAccessTest extends TestCase
 {
-    /** @var SQLite3 */
-    protected $database = null;
+    /** @var Opf\Models\SCIM\Standard\Groups\CoreGroup */
+    protected $coreGroup = null;
 
-    /** @var array */
-    protected $dbSettings = null;
-
-    /** @var Illuminate\Database\Capsule\Manager */
-    protected $capsule = null;
-
-    /** @var Opf\Models\CoreGroup */
+    /** @var Opf\DataAccess\Groups\MockGroupDataAccess */
     protected $mockGroupDataAccess = null;
 
+    /** @var Opf\Opf\Adapters\Groups\MockGroupAdapter */
+    protected $mockGroupAdapter = null;
+
     public function setUp(): void
     {
-        $this->database = new SQLite3(__DIR__ . '/../resources/test-scim-opf.sqlite');
-
-        $groupDbSql = "CREATE TABLE IF NOT EXISTS groups (
-            id varchar(160) NOT NULL UNIQUE,
-            displayName varchar(160) NOT NULL DEFAULT '',
-            members TEXT NOT NULL DEFAULT '',
-            created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            updated_at DATETIME NULL
-        )";
-
-        $this->database->exec($groupDbSql);
-
-        $createGroupSql = "INSERT INTO groups (
-            id,
-            displayName,
-            members
-            ) VALUES (
-                '12345678-9012-3456-7890-12345679',
-                'testGroup',
-                '12345678-9012-3456-7890-12345678'
-        )";
-
-        $this->database->exec($createGroupSql);
-
-        $this->dbSettings = [
-            'driver' => 'sqlite',
-            'database' => __DIR__ . '/../resources/test-scim-opf.sqlite',
-            'prefix' => ''
-        ];
-
-        $this->capsule = new Manager();
-        $this->capsule->addConnection($this->dbSettings);
-        $this->capsule->setAsGlobal();
-        $this->capsule->bootEloquent();
-
+        Util::setConfigFile(__DIR__ . '/../resources/mock-test-config.php');
+        $this->coreGroup = new CoreGroup();
+        $this->mockGroupAdapter = new MockGroupAdapter();
         $this->mockGroupDataAccess = new MockGroupDataAccess();
     }
 
     public function tearDown(): void
     {
+        $this->coreGroup = null;
+        $this->mockGroupAdapter = null;
         $this->mockGroupDataAccess = null;
-        $this->capsule = null;
-        $this->dbSettings = null;
-        $this->database->exec("DROP TABLE groups");
-        $this->database = null;
-
-        unlink(__DIR__ . '/../resources/test-scim-opf.sqlite');
-    }
-
-    public function testReadAllGroups()
-    {
-        $this->assertNotEmpty($this->mockGroupDataAccess->all());
     }
 
     public function testCreateGroup()
     {
         $testGroupJson = json_decode(file_get_contents(__DIR__ . '/../resources/testGroup.json'), true);
-        $this->mockGroupDataAccess->fromSCIM($testGroupJson);
-        $groupCreateRes = $this->mockGroupDataAccess->save();
-        $this->assertTrue($groupCreateRes);
+        $this->coreGroup->fromSCIM($testGroupJson);
+        $mockGroup = $this->mockGroupAdapter->getMockGroup($this->coreGroup);
+        $groupCreateRes = $this->mockGroupDataAccess->create($mockGroup);
+        $this->assertNotNull($groupCreateRes);
+    }
+
+    public function testReadAllGroups()
+    {
+        $this->assertNotEmpty($this->mockGroupDataAccess->getAll());
     }
 }
diff --git a/test/unit/MockUsersDataAccessTest.php b/test/unit/MockUsersDataAccessTest.php
index 3f1c347..71a1e71 100644
--- a/test/unit/MockUsersDataAccessTest.php
+++ b/test/unit/MockUsersDataAccessTest.php
@@ -4,88 +4,49 @@ namespace Opf\Test\Unit;
 
 use PHPUnit\Framework\TestCase;
 use Illuminate\Database\Capsule\Manager;
+use Opf\Adapters\Users\MockUserAdapter;
 use Opf\DataAccess\Users\MockUserDataAccess;
+use Opf\Models\SCIM\Standard\Users\CoreUser;
+use Opf\Util\Util;
 use SQLite3;
 
 final class MockUsersDataAccessTest extends TestCase
 {
-    /** @var SQLite3 */
-    protected $database = null;
+    /** @var Opf\Models\SCIM\Standard\Users\CoreUser */
+    protected $coreUser = null;
 
-    /** @var array */
-    protected $dbSettings = null;
-
-    /** @var Illuminate\Database\Capsule\Manager */
-    protected $capsule = null;
-
-    /** @var Opf\Models\MockUser */
+    /** @var Opf\DataAccess\Users\MockUserDataAccess */
     protected $mockUserDataAccess = null;
 
+    /** @var Opf\Adapters\Users\MockUserAdapter */
+    protected $mockUserAdapter = null;
+
     public function setUp(): void
     {
-        $this->database = new SQLite3(__DIR__ . '/../resources/test-scim-opf.sqlite');
-
-        $userDbSql = "CREATE TABLE IF NOT EXISTS users (
-            id varchar(160) NOT NULL UNIQUE,
-            userName varchar(160) NOT NULL,
-            active BOOLEAN NOT NULL DEFAULT 1,
-            externalId varchar(160) NULL,
-            profileUrl varchar(160) NULL,
-            created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
-            updated_at DATETIME NULL
-        )";
-
-        $this->database->exec($userDbSql);
-
-        $createUserSql = "INSERT INTO users (
-            id,
-            userName,
-            externalId,
-            profileUrl
-            ) VALUES (
-            '12345678-9012-3456-7890-12345678',
-            'testuser',
-            'testuserexternal',
-            'https://example.com/testuser'
-        )";
-
-        $this->database->exec($createUserSql);
-
-        $this->dbSettings = [
-            'driver' => 'sqlite',
-            'database' => __DIR__ . '/../resources/test-scim-opf.sqlite',
-            'prefix' => ''
-        ];
-
-        $this->capsule = new Manager();
-        $this->capsule->addConnection($this->dbSettings);
-        $this->capsule->setAsGlobal();
-        $this->capsule->bootEloquent();
-
+        Util::setConfigFile(__DIR__ . '/../resources/mock-test-config.php');
+        $this->coreUser = new CoreUser();
         $this->mockUserDataAccess = new MockUserDataAccess();
+        $this->mockUserAdapter = new MockUserAdapter();
     }
 
     public function tearDown(): void
     {
+        $this->coreUser = null;
         $this->mockUserDataAccess = null;
-        $this->capsule = null;
-        $this->dbSettings = null;
-        $this->database->exec("DROP TABLE users");
-        $this->database = null;
-
-        unlink(__DIR__ . '/../resources/test-scim-opf.sqlite');
-    }
-
-    public function testReadAllUsers()
-    {
-        $this->assertNotEmpty($this->mockUserDataAccess->all());
+        $this->mockUserAdapter = null;
     }
 
     public function testCreateUser()
     {
         $testUserJson = json_decode(file_get_contents(__DIR__ . '/../resources/testUser.json'), true);
-        $this->mockUserDataAccess->fromSCIM($testUserJson);
-        $userCreateRes = $this->mockUserDataAccess->save();
-        $this->assertTrue($userCreateRes);
+        $this->coreUser->fromSCIM($testUserJson);
+        $mockUser = $this->mockUserAdapter->getMockUser($this->coreUser);
+        $userCreateRes = $this->mockUserDataAccess->create($mockUser);
+        $this->assertNotNull($userCreateRes);
+    }
+
+    public function testReadAllUsers()
+    {
+        $this->assertNotEmpty($this->mockUserDataAccess->getAll());
     }
 }