Google Authentication

Configure the OAuth Consent Screen

1. Create a New Project:
• Go to the Google Cloud Console.
• Click on the project dropdown in the top left corner and select “New Project.”
• Give your project a name and click Create.
2. Set Up OAuth Consent Screen:
• Navigate to APIs & Services → OAuth Consent Screen.
3. Fill in App Information:
• App name: Enter your app's name.
• User support email: Enter a contact email.
• App logo: (Optional) Upload your app's logo.
• App domain: If you own a domain, enter it here.
• Authorized domains: Add your production domain(s) and your Supabase project domain (e.g., PROJECT_ID.supabase.co, you can find it in Supabase Dashboard → Project Settings → API)
• Developer contact information: Enter your email address.
• Click "Save and Continue."
4. Open the Audience tab in your Google Cloud project (OAuth consent screen settings).
• Confirm that User type is set to External (default for most projects).
• Check the Publishing status: by default it is Testing. For production, click Publish app.
• If the app remains in Testing, add your Google accounts under Test users.
5. Scopes:
• Click "Add or Remove Scopes" and add the required scopes for your app. For basic Google authentication, you’ll need openid, email, and profile.
• Click "Save and Continue."

Create OAuth 2.0 Client IDs

1. Web Client (required for Supabase OAuth)

1. Go to APIs & Services → Credentials.
2. Click Create Credentials → OAuth Client ID.
3. Select Web Application.
4. Name the client (e.g., “Expo Web Client”).
5. Add Authorized redirect URIs: Copy the Callback URL directly from your Supabase dashboard (e.g. https://<project-ref>.supabase.co/auth/v1/callback)
6. Click Create.
7. Save the Client ID and Client Secret — you’ll need them for Supabase.

2. Android Client

1. Click Create Credentials → OAuth Client ID.
2. Select Android.
3. Name it (e.g., “Expo Android Client”).
4. Enter your Android package name (e.g., com.nativelaunch.app).
5. Add SHA-1 fingerprints:
Recommendation

Create two clients: one for development, one for production.

Here is an example of how I did it on my application:

Development SHA-1: Run:

keytool -list -v -keystore ./android/app/debug.keystore \
-alias androiddebugkey \
-storepass android -keypass android

Production SHA-1: In Play Console → Setup → App Integrity → App signing certificate.



6. Click Create and save the Client ID.
7. Note: You do not use the Android Client ID directly in your Expo app. Instead, add it to Supabase along with the iOS Client ID.

3. iOS Client

1. Click Create Credentials → OAuth Client ID.
2. Select iOS.
3. Name it (e.g., “Expo iOS Client”).
4. Enter your iOS bundle identifier (e.g., com.nativelaunch.app).
5. Click Create.
6. After creation, open the client and copy the iOS URL Scheme (REVERSED_CLIENT_ID).
7. Note: The iOS Client ID is required both in your Expo code (iosClientId) and in Supabase (comma-separated with the others).

Update .env

EXPO_PUBLIC_GOOGLE_WEB_CLIENT_ID=*****
EXPO_PUBLIC_GOOGLE_IOS_CLIENT_ID=*****

Get iOS URL Scheme

In your Google Cloud project, navigate to APIs & Services > Credentials. Click on the iOS OAuth Client you created. Copy the iOS URL Scheme.

Update the values in your app.json file:

export default {
  expo: {
    plugins: [
      [
        "@react-native-google-signin/google-signin",
        {
          "iosUrlScheme": "com.googleusercontent.apps.xxxxxxxx"
        }
      ]
    ]
  }
}

Enable Google Provider

• Open your Supabase Dashboard.
• Go to Authentication → Providers.
• Enable Google.
• Paste all your Client IDs (Web, Android, iOS) comma-separated, and the Client Secret from the Web client.

Redirect URLs

• Supabase shows you the correct Callback URL (e.g. https://<project-ref>.supabase.co/auth/v1/callback).
• Copy this and add it to your Google Cloud Web Client under Authorized redirect URIs.

Test Your Setup

• If you're using a simulator, make sure it supports iOS 13 or later (required for Sign In with Apple).

• If you have a device, you can test the authentication flow more accurately.