How to find out Callback URI of the Windows 10 App?

Usually, when implementing AAD authentication in application, according to OAuth protocol, you will have to provide so called Callback-URI. This is the URL of the endpoint capable of receiving redirected request from authority.  Because the specification as originally written for web applications, this kind of URL is not natural for native apps.

Depending on type of operative system or even better, depending on client library, which you use, this URL might look different. In a case of UWP (Universal Windows Application), the URL  can be extracte as follows:

string URI = string.Format("ms-appx-web://Microsoft.AAD.BrokerPlugIn/{0}", WebAuthenticationBroker.GetCurrentApplicationCallbackUri().Host.ToUpper());

As a result you will get something like this:

ms-appx-web://Microsoft.AAD.BrokerPlugIn/S-1-XX-2-00000000-11111-22222-4444-2290055178-222222-1111111

This URL is what you have to set in application blade in Azure AAD portal.