Google Sign-in with Firebase Authentication - Expo React Native Application

In this step-by-step guide, learn how to implement Google Sign-In with Firebase Authentication in your Expo React Native app for both Android and iOS. This tutorial covers everything — from setting up Firebase and configuring SHA-1 keys to handling Google login flows, debugging, and getting it working across platforms with expo prebuild. Perfect for anyone struggling with the hidden gotchas of Google Auth in Expo.

⏱️ Timestamps:
00:00 - Intro and pre-requisites
00:45 - Firebase setup reminder
01:15 - Why Google Sign-In is multi-step
02:00 - Start with Android integration
03:00 - Installing required libraries
04:00 - Understanding the free vs paid Google Auth libraries
05:00 - Editing app.json for Expo config plugins
06:00 - Running expo prebuild for native code
07:00 - Enabling Google Sign-In in Firebase Console
08:30 - Creating the Google Sign-In button component
10:00 - Centering and styling the button
11:00 - Google Sign-In library internal flow explained
12:00 - Debugging non-working sign-ins
13:00 - SHA-1 and Keystore overview
14:00 - Using KeyStore Explorer to get SHA-1
15:00 - Adding SHA-1 to Firebase
16:30 - Importance of release SHA-1 and Play Console SHA-1
18:00 - Summary of common missteps
19:00 - Hooking up onPress logic
20:00 - Missing scopes and client ID fix
21:00 - Getting Web Client ID from google-services.json
22:30 - Rebuilding and re-testing the flow
23:30 - Confirming success in Firebase Authentication tab
24:00 - Emulator must-have: Google Play Store
25:30 - Adding missing Google SDK scopes
27:00 - Troubleshooting common errors
28:00 - Sign in and sign out with console logs
30:00 - Displaying email and UID after sign-in
31:00 - Integrating onAuthStateChanged logic
32:00 - Role of UID in Firestore or Postgres
33:00 - Implementing protected routes in Expo Router
34:00 - Final test: working Google Sign-In in Android & iOS
35:00 - Recap & preview of next video for bare React Native

Links mentioned in the video:

https://docs.expo.dev/guides/google-a...

https://rnfirebase.io/auth/social-aut...

https://react-native-google-signin.gi...

You can email me at for further queries: gauthamvijay495@gmail.com

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🏷️ Hashtags:
#GoogleSignIn #FirebaseAuth #Expo #ReactNative #AndroidDev #iOSDev #ExpoPrebuild #FirebaseAuthentication #SHA1Key #WebClientID #MobileAuth #ReactNativeFirebase #GoogleAuth #AppSecurity #AuthFlows #DebuggingTips