Bundled with the new ASP.NET MVC 4 offering is the open-source ASP.NET Web API designed to streamline the development and deployment of RESTful services. Unlike WCF REST or ASP.NET AJAX with ASMX, ASP.NET Web API is a new platform versus simply being a bolt-on technology that is would be intended to work in the context of an existing framework. ASP.NET Web API’s strength is that it combines the best features of the platforms that came before it in order to provide a complete and very usable HTTP platform. Because it's based on ASP.NET and borrows a lot of concepts from ASP.NET MVC, Web API should be immediately familiar and comfortable to most ASP.NET developers. Read the full story here.
In line with Microsoft’s recent unveiling of their Visual Studio 2012 and .NET 4.5 launch, Microsoft formally unveiled its new web services framework called the ASP.NET Web API.