I made Login flow app with Google sign in feature and it includes phone verification feature as well. I used Firebase As a backend.
I used Firebase to use Google sign In feature, Phone number verification and storing Users data.
dependencies {
implementation 'com.google.firebase:firebase-auth:19.3.1'
implementation 'com.google.android.gms:play-services-auth:18.0.0'
implementation 'com.googlecode.libphonenumber:libphonenumber:8.9.7'
implementation 'com.google.firebase:firebase-database:19.3.0
implementation 'androidx.cardview:cardview:1.0.0'
implementation 'com.google.android.material:material:1.1.0'
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}