Google One Tap

When users visit your website, if there is an active Google session in the browser, Sign in with Google may prompt users to sign in or sign up on your website with their Google Account. With just one tap (for a single Google session case) or two taps (when there are multiple Google sessions), users can finish the federated sign-in or sign-up flow. The One Tap UX allows for smooth user entry points, since all the UX flows are performed in an iframe embedded in your web pages.