title: Facebook app (NOT user) access token expiration
body: <p>Do Facebook APP access tokens expire? These tokens are different than the USER tokens; they are acquired like this:</p>
  
  <pre><code>https://graph.facebook.com/oauth/access_token?grant_type=client_credentials&amp;client_id={0}&amp;client_secret={1})
  </code></pre>
  
  <p>as described in the App Login section of the document at <a href="http://developers.facebook.com/docs/authentication/">http://developers.facebook.com/docs/authentication/</a>.</p>
  
  <p>Are there any circumstances under which they will become invalid?</p>
  
  <p>NB: This is NOT a question about USER access tokens (which are clearly documented). There was an identical question <a href="http://facebook.stackoverflow.com/questions/7322063/does-app-login-access-token-expire">http://facebook.stackoverflow.com/questions/7322063/does-app-login-access-token-expire</a> wrongly closed as duplicate of another question about USER access tokens.</p>