Azure Active Directory is a great product and is invaluable in the enterprise space. In this article we'll be setting it up to provide tokens for the OAuth2 client credentials grant. This authorization flow is useful when you want to authorize server-to-server communication that might not be on behalf of a user. This diagram, by Microsoft, shows the client credentials grant flow. From Microsoft documentation The flow goes like this: The client sends a request to Azure AD for a token Azure AD verifies the attached authentication information and issues an access token The client calls the API with the access token. The API server is able to verify the validity of the token and therefore the identity of the client. The API responds to the client Setting up Azure AD as an OAuth2 identity provider The first step is to create applications in your AD for both your API server and the client. You can find step-by-step instructions on how to register the applications o...