I have a Web Api project that I have already configured to use Facebook & Google authentication.
Facebook and Google both have a way of verifying the access token given on authentication step.
Facebook: https://graph.facebook.com/debug_token?input_token={0}&access_token={1}", accessToken, appToken
These return the app_id or consumer key for my applications.
What is the process for Twitter?
The documentation I have read isn't very clear and what I have tried fails and returns a 404.