Implementing Google Sign-in authentication

Google authentication is the process of logging in/creating an account using nothing but your existing Google account. It's easy, fast, and intuitive and removes a lot of hustle we face, usually when we register any web/mobile application. I'm talking basically about form filling. Using Firebase Google Sign-in authentication, we can manage such functionality; plus we have had the user basic metadata such as the display name, picture URL, and more. In this recipe, we're going to see how we can implement Google Sign-in functionality for both Android and iOS.

Getting ready...

Before doing any coding, it's important to do some basic configuration in our Firebase Project...