An *Authorization API Token* or *AAT* is a special OAuth2 Access Token with the scope *uma_authorization*. When you create an user, {{book.project.name}} automatically
assigns a role _uma_authorization_ to the user. The _uma_authorization_ role is a _default realm role_ as you can see from this page.
.Default Role uma_authorization
image:../../../images/service/rs-uma-authorization-role.png[alt="Default Role uma_authorization "]
An AAT means that a client application is allowed to query the server for user permissions.
Client applications can obtain an AAT from {{book.project.name}} just like any other OAuth2 Access Token. Usually, client applications obtain AATs after the user is successfully
authenticated in {{book.project.name}}. By default the _authorizaton_code_ grant type is used to authenticate users and issue an OAuth2 Access Token to the client application acting on their behalf.