ASP.NET Identity is a totally rewritten framework that brings the ASP.NET membership system into the modern era. ASP.NET Identity makes it easier to integrate different authentication systems such as local username, password as well as social logins such as Facebook, Twitter etc. It also gives you greater control over persisting data to your backend technology of choice. ASP.NET Identity is a game changer by bringing in more modern authentication systems such as Two-Factor Authentication. You can use ASP.NET Identity to secure Web Apps as well as Web APIs.