title: What is callback url in instagram api and how to can I implement it
body: <p>Hi I'm beginner programmer</p>
  
  <p>I'm trying to use instagram's realtime Photo Updates api</p>
  
  <p>My purpose is use this API CONSOLE's subscription method <br>
  <a href="https://apigee.com/console/instagram" rel="noreferrer">https://apigee.com/console/instagram</a></p>
  
  <p>But I can't understand and handle callback url</p>
  
  <p>What is the callback url's function?</p>
  
  <p>And How can I implement the callback url?</p>