Is Google login API free?
Google Sign-in is a free service.
Is Google sign in an API?
Google Sign-In manages the OAuth 2.0 flow and token lifecycle, simplifying your integration with Google APIs. A user always has the option to revoke access to an application at any time. This document describes how to complete a basic Google Sign-In integration.
Is Google in oauth2 sign in?
Google APIs use the OAuth 2.0 protocol for authentication and authorization. Google supports common OAuth 2.0 scenarios such as those for web server, client-side, installed, and limited-input device applications. To begin, obtain OAuth 2.0 client credentials from the Google API Console.