title: Do facebook app tokens expire?
body: <p>I'm reading up on <a href="https://developers.facebook.com/docs/facebook-login/access-tokens/" rel="nofollow">Facebook Access Tokens</a>. I need to generate an app token to inspect an access token I got from a user. This is described <a href="https://developers.facebook.com/docs/facebook-login/login-flow-for-web-no-jssdk/#confirm" rel="nofollow">here</a>, but isn't that relevant now.</p>
  
  <p>I can write software which generates an app token through the access_token endpoint every time I need to inspect a user's access token. However, that would take some time, and I'd like to avoid it if possible.<br>
  <strong>I would like to know if these app tokens can expire.</strong></p>
  
  <p>If not, is it a good idea to just store the app token in plaintext in my (server-side) code? That way I can reduce HTTP requests to the API.</p>