If you want to use the ASP.NET Web API in a conventional ASP.NET web application and use it to post back the entire objects to the server, read this article here. This article explains step by step on how to post Data to ASP.NET sites with ASP.NET web API. From the first step, the article defines how to add the Add New Item menu in an ASP.NET API controller class to your project. The next step explains how you can code the client using the JQuery code, add buttons, attach the buttons, and writing a function to send the data to the server. Then you need to code the server which will help define the Customer object you want to load you JSON data when it gets to the client.
Read full instructions here: http://visualstudiomagazine.com/articles/2012/09/07/asp-net-web-api.aspx