title: Why do we need web API in MVC? What's the drawback in restful api in mvc?
body: <p>I am new to ASP.NET Web API. Can anyone please tell me </p>
  
  <ul>
  <li>Why we need Web API?</li>
  <li>How it differs from rest full api from MVC ? </li>
  <li>When to use MVC4 web api ?</li>
  <li>What is restful api in MVC</li>
  </ul>