title: Is the Google Sign-In API free to use?
body: <p>I'm searching for a good way to make authentication on my own website. </p>
  
  <p>Just wondering if the <a href="https://developers.google.com/identity/sign-in/web/" rel="nofollow noreferrer">Google Sign-In API</a> is free to use or not. Are there differences to the Cloud Identity?</p>