keycloak-scim/docbook/auth-server-docs/reference/en/en-US/modules/installed-applications.xml

<section id="installed-applications">
    <title>Installed Applications</title>
    <para>
        Keycloak provides two special redirect uris for installed applications.
    </para>
    <section id="installed-applications-url">
        <title>http://localhost</title>
        <para>
            This returns the code to a web server on the client as a query parameter. Any port number is allowed.
            This makes it possible to start a web server for the installed application on any free port number without
            requiring changes in the <literal>Admin Console</literal>.
        </para>
    </section>
    <section id="installed-applications-urn">
        <title>urn:ietf:wg:oauth:2.0:oob</title>
        <para>
            If its not possible to start a web server in the client (or a browser is not available) it is possible to
            use the special <literal>urn:ietf:wg:oauth:2.0:oob</literal> redirect uri. When this redirect uri is used
            Keycloak displays a page with the code in the title and in a box on the page. The application can either
            detect that the browser title has changed, or the user can copy/paste the code manually to the application.
            With this redirect uri it is also possible for a user to use a different device to obtain a code to paste
            back to the application.
        </para>
    </section>
</section>