Feb 14, 2012 at 2:15 AM
Edited Feb 14, 2012 at 2:15 AM
It's a night and day difference.
The main feature of the REST Starter Kit is the HTTP Client for consuming web apis along with a few server bits namely the RequestInterceptor.
Web API (now ASP.NET Web API) includes a completely new server stack for hosting web apis. It offers very rich control of HTTP thus providing an exponentially richer experience for building truly RESTful services and for supporting a range of devices.
HttpClient has now been productized and is part of the .NET framework / on nuget. But Web API allows you to take the new HttpRequestMessage and HttpResponseMessage and use those messages on the server in the same way you can on the client. It also offers
a full content negoitation stack allowing you to support a rich range of media types beyond simply XML and JSON.
post discusses the initial drivers / why we did web api in the first place. The APIs have changed quite a bit from those days but it gives all the reasoning.
Here's a recent blog post highlighting it's features.
And here is a forum post that shows where web api is going as part of the merger with MVC.