title: Can Cloud Functions for Firebase execute on user login?
body: <p>I see how execute a Cloud Function on user account creation:</p>
  
  <pre><code>exports.myFunction = functions.auth.user().onCreate(event =&gt; { 
  </code></pre>
  
  <p>But I need my function to execute when the user logs in. Is there a <code>onLogin</code> trigger?</p>
  
  <p>And can someone with 1500 points create a tag for <code>firebase-cloud-functions</code>?</p>