Firebase is a google's mobile platform that helps us to develop high-quality apps in minimum effort. Firebase provides Authentication library to authenticate users, you don't need to save user data on your local server because firebase saves that all.
There are lots of ways to authenticate use like using Google login, phone authentication, email login, Facebook, twitter etc.
Here we will work with google login, so follow the below steps to integration firebase authentication :
1. Go to https://console.firebase.google.com and create a new project
2. Now go to the side panel and click on Authentication option there you will see further options like email, phone, google etc, so click on google one.
3. Click on enable button and save changes.
4. Go to this link and set your SHA fingerprint here https://developers.google.com/android/guides/client-auth to generate SHA
5. Go to your project settings and enter SHA and package name there to generate google services json file and after downloading that paste that in your project main folder.
6. Now you are done with google console so add these dependencies in App Gradle file :