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 console.

Head directly to your Firebase project Console | Authentication | SIGN-IN METHOD | Google and simply activate the switch and follow the instructions there in order to get the client. Please notice that Google Sign-in is automatically configured for iOS, but for Android, we will...