Automatic sign-in and sign-out

This page describes how to implement features related to how users sign in or sign out with Google One Tap.

Sign in users automatically

Google One Tap supports automatic sign-in, which provides a frictionless user experience (UX) by removing the manual steps users must take when returning to your site. Users don't need to remember which Google Account they selected during their last visit, decreasing the chances of unnecessary duplicate accounts being created on your platform.

Automatic sign-in is intended to complement our Sign in with Google button and One Tap dialogs. It is designed to be used across your entire site, with manual sign-up or switching accounts occurring only after the user has first signed-out of your site.

For Automatic sign-in to occur the following conditions are required:

  • users must first be signed-in to their Google Account, and
  • previously granted consent to share their account profile with your app, and
  • when using FedCM, made only a single sign-in attempt in the last 10 minutes. One Tap is displayed when repeated sign-in attempts occur during this window.
  • when using FedCM, Chrome requires users to reconfirm that they want to sign in to the website with Google Account in each Chrome instance even if the user approved the website prior to the FedCM rollout. This change may affect conversion rate on your existing site using One Tap. In Chrome M121 update, Auto Sign-in improvement mitigates conversion rate drop issue.

For pages where Automatic sign-in is enabled and if these conditions are met the user's ID token credential is automatically returned without any user interaction. If these conditions are not met, and even if Automatic sign-in is enabled on the page, the user defaults to the One Tap flow for sign-in or consent. If a user has multiple Google Accounts and visits your site they are required to first sign-in to a single Google Account and to have provided consent for that account.

You may measure Automatic sign-in success rate using the auto value in the select_by field of the returned credential object.

To enable automatic sign-in, add data-auto_select="true" to your code, as shown in the following snippet:

<div id="g_id_onload"
     data-client_id="YOUR_GOOGLE_CLIENT_ID"
     data-login_uri="https://your.domain/your_login_endpoint"
     data-auto_select="true">
</div>

Sign out

When a user signs out of your website, they can be directed to a page where a Google One Tap prompt is automatically displayed. For this setup, auto-selection must be prohibited. Otherwise, the user is automatically signed in again, which leads to a dead-loop UX.

Using FedCM

To improve user experience, there is a 10 minute quiet period between every automatic sign-in attempt. During this time period, One Tap prompt is displayed instead. Users need to explicitly click One Tap to sign in.

Without FedCM

To prohibit auto-selection after a user signs out, add the class name g_id_signout to all of your logout links and buttons. See the following code snippet:

<div class="g_id_signout">Sign Out</div>

The following JavaScript code snippet can also be used for sign out:

const button = document.getElementById('signout_button');
button.onclick = () => {
  google.accounts.id.disableAutoSelect();
}

To prevent a dead-loop UX, user signed-out status is stored in a cookie named g_state that is set by the Google Identity Services library. By default the cookie domain is set to the domain of current page. If One Tap is displayed on the parent domain and subdomains, the state cookie must be visible across all of your domains. Use the data-state_cookie_domain attribute to set the g_state cookie domain to your parent domain. For example, add data-state_cookie_domain="example.com" to the g_id_onload element for a parent domain of example.com and a subdomain named webapp.example.com.

If you have a service that monitors all of the cookies used in your domain, you need to notify them of the g_state cookie.

If you don't want to load the client library on your post-login pages, use these solutions to prevent a dead-loop UX after log out occurs:

  • On log out, redirect users to a page (say, https://example.com/logged_out) where One Tap is not displayed, or where auto sign-in is always disabled.
  • On log out, add a parameter to the URL. For example, logged_out=1. When rendering One Tap by JavaScript API, check that URL parameter and disable auto sign-in when present.

Key user journeys

The automatic sign-in page.

Using FedCM

FedCM automatic sign-in popup

Users can close the One Tap prompt by clicking the X button. For accessibility consideration, an ID token is shared with your website even if users click the X button.

To improve user experience, there is a 10 minute quiet period between every automatic sign-in attempt. During this time period, One Tap prompt is displayed instead. Users need to explicitly click One Tap to sign in.

Without FedCM

An example of an automatic sign-in popup.

If users don't click the Cancel button within 5 seconds, an ID token is shared with your website.

When Sign-In is cancelled, based on the number of active Google sessions, either the account chooser page or the returning user page displays.

  • Multiple Google sessions

An example of an Account Chooser page

  • Single Google Sessions

One Tap returning user page