Self-Hosting an ASP.NET Web API

ASP.NET Web API can be either be hosted in IIS or in a separate host process. The former approach is usually appropriate when the Web API is part of a web application and one or more web applications are going to consume it. The later approach is suitable when you wish to avoid the overhead of hosting the Web API in IIS and want to have something lightweight. Hosting a Web API inside IIS is quite straightforward as the process is identical to hosting a web application. On the other hand, hosting a Web API in it's own process requires the creation of a host application and is referred as self-hosting. This article shows in step-by-step manner how to self-host a Web API and how to consume it using a client application.

http://www.binaryintellect.net/articles/0de7c320-cef5-45dc-a801-dcdb4905ed71.aspx