ASP.NET Web API is Framework for building for building HTTP services on top of the .NET Framework. It ships with ASP.NET MVC 4. You can install the ASP.NET MVC 4 from here. ASP.NET Web API is a integrated Framework resulted in joint effort from WCF and ASP.NET teams. WCF REST is now replaced by ASP.NET Web API. You can read the post to migrate your existing WCF Web API to ASP.NET Web API. This post briefly discuss about why we need it and how we can use it in ASP.NET and other projects.