Load the Google Identity Services JavaScript Library

Page Summary

• The Google 3P Authorization JavaScript library is required for pages handling OAuth 2.0 codes or tokens and can be loaded using a provided script snippet.

• Loading the script with async and defer attributes can optimize page loading speed.

Be sure to load the Google Identity Services JavaScript library (https://accounts.google.com/gsi/client) on any web page where a user might initiate an OAuth 2.0 authorization flow to obtain authorization codes or access tokens. Use the following <script> snippet in your HTML <head> or <body>:

<script src="https://accounts.google.com/gsi/client" async></script>

You can optimize your page's loading speed by loading the script with the async attribute. If your script initializes a token client (google.accounts.oauth2.initTokenClient) or code client (google.accounts.oauth2.initCodeClient) immediately upon load, you can attach an onload callback handler to the <script> tag:

<script src="https://accounts.google.com/gsi/client" onload="initClient()" async></script>

Refer to the Google Account Authorization JavaScript API reference for the complete list of methods and configuration properties that the google.accounts.oauth2 namespace supports.

Note: The Google Identity Services library must be loaded directly from https://accounts.google.com/gsi/client using a <script> element in your web page. This ensures your integration always receives security updates and compatibility fixes. Self-hosting or bundling an offline copy of the script is not supported and may lead to unexpected failures.

Next steps

After loading the client library, choose the authorization model that matches your application architecture:

• Choose a user authorization model to compare the authorization code and implicit grant flows.
• Use the authorization code model (recommended for apps with a backend server).
• Use the token model (for client-side, browser-only apps).