title: Is it good to use not standard HTTP status codes in REST responce?
body: <p>Is it good idea to use status codes not described in HTTP standard for  REST responses of a REST API? </p>
  
  <p>For example:</p>
  
  <ul>
  <li>470 or 770 - "User account not found"  </li>
  <li>471 or 771 - "User account
  avatar not found"</li>
  </ul>
  
  <p>What can be a  problem except coincidence with a new status code of    the standard? </p>
  
  <p>Is there a codes range can be used for REST API special    needs?</p>