title: How to handle a callback url in React
body: <p>I am building a full-stack application, where users upload videos and the server does some manipulation and eventually informs the user if the conversion is complete.</p>
  
  <p>On the front-end, I have React and close the connection, when the upload is finished. In the meantime my server does the conversion and I would like to find a way to inform my front-end that the conversion has finished. How could I do this? Maybe through using some callback url? Thank you</p>