This ASP.NET backend retrieve information of authenticated users with Facebook, Google, Twitter and Microsoft account. It returns user information as a json string. Also, the classes of these strings are included in project.
Firstly, you need to create developer applications to establish communication between your application and Facebook, Twitter, Microsoft and Google. Here is some good instructions to create developer applications provided by Microsoft Azure.
Do not forget to click "Request e-mails" checkbox on Twitter App Management console.
After you completed application registration, you need to enable Authentication on Azure portal. Open your app and go Authentication. Click 'On' and set unauthenticated option to 'No Action'.
Facebook Permissions
Microsoft Permissions
Google Permissions
Twitter Permissions
Also, you need to re-write your App key and secret on codebehind.
Feel free to ask questions via 'Issues'.