Google Sign-In

A secure authentication framework that lets 2.5 billion active users log into third party apps using their existing Google credentials.

Google Sign-In (now integrated into Google Identity Services) streamlines user onboarding by replacing manual forms with a single tap. It utilizes OAuth 2.0 and OpenID Connect protocols to securely share profile data (names, emails, and photos) without exposing passwords. Developers manage integration via the Google Cloud Console: requiring only a Client ID and the 'gis' JavaScript library to get started. This system offloads credential security to Google's infrastructure while increasing sign-up conversion rates by up to 40 percent: a direct result of reduced friction and improved trust.

https://developers.google.com/identity/gsi/web/guides/overview