Google Sign-in is a free service . To use Google sign-in you have to use Google’s Firebase authentication service. Pricing for Firebase has three tiers, you can see the pricing at this link https://firebase.google.com/pricing/.
Read moreHow do I integrate with Google sign in?
Integrating Google Sign-In into your web app
Read moreHow do I sign into Google account on Android?
Integrating Google Sign-In into Your Android App
Read moreHow do I integrate Google login in flutter?
Flutter – Google Sign in UI and Authentication
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