How do I set up social login for a mobile app?

To set up social login for a mobile app, the usual approach is:

1) Choose the providers

Common options:

• Google
• Apple
• Facebook
• Microsoft
• GitHub (more common for developer tools)

Pick based on your users and platform:

• iOS apps: Apple login is often required if you offer other social logins.
• Android apps: Google is usually the most common.
• If you need broad coverage, support 2–3 providers.

2) Decide your auth architecture

There are two common patterns:

A. Use a backend as the “source of truth” (recommended)

Flow:

1. User taps “Continue with Google/Apple/etc.”
2. App gets an ID token / auth code from the provider
3. App sends that token/code to your backend
4. Backend verifies it with the provider
5. Backend creates or links a user account
6. Backend issues your app a session token or JWT

Why this is best:

• You control user accounts
• Easier to link multiple login methods
• Better security and session management

B. Let the mobile app talk directly to your backend-less service

This is simpler, but less flexible. Often used with services like:

• Firebase Authentication
• Auth0
• AWS Cognito

3) Register your app with each provider

You’ll need to create developer credentials on each platform:

Google

• Create a project in Google Cloud Console
• Configure OAuth consent screen
• Create OAuth client IDs for iOS/Android/web as needed

Apple

• Use Apple Developer account
• Enable “Sign in with Apple”
• Configure Service ID / App ID and keys

Facebook

• Create an app in Meta for Developers
• Configure OAuth redirect URLs, bundle ID, and app secret

Each provider will give you:

• Client ID
• Redirect URI settings
• Sometimes a client secret or signing key

4) Implement the mobile login flow

Usually via an SDK:

iOS

• Use provider SDKs or system-supported flows
• Apple: AuthenticationServices
• Google/Facebook: their native SDKs

Android

• Use provider SDKs
• Often through OAuth in a browser-based flow or SDK wrappers

Best practice

Use:

• Authorization Code Flow with PKCE for mobile
• Avoid embedding secrets in the app
• Prefer secure system browser / ASWebAuthenticationSession / Chrome Custom Tabs over raw webviews

5) Verify identity on your backend

When the app sends a token or code:

• Validate the token signature
• Check issuer, audience, expiration
• Confirm the user ID (sub) from the provider
• Create/link a local user record

If using auth codes:

• Exchange the code for tokens on the backend
• Then validate ID token or user info

6) Issue your own app session

After verification, your backend should issue:

• a JWT access token
• optionally a refresh token
• or a server session cookie if applicable

Your app should use your own token for API requests, not the social provider token directly.

7) Handle account linking

Users may sign in with:

• Google on Android
• Apple on iPhone
• Email on web later

Design account linking rules:

• Match by verified email only if appropriate
• Prefer a stable provider ID
• Let users link/unlink providers in account settings

8) Add logout and account deletion

Implement:

• App logout: clear local tokens
• Optional provider logout/revoke if needed
• Account deletion flow to comply with store policies and privacy laws

9) Test edge cases

Test:

• First login vs returning login
• Cancel flow
• Expired tokens
• User denying email/profile access
• Sign in on multiple devices
• Apple private relay email behavior
• Account linking conflicts

10) Consider using an auth platform

If you want to avoid building and maintaining this yourself, use:

• Firebase Authentication
• Auth0
• AWS Cognito
• Supabase Auth
• Clerk

These handle most of the OAuth/OIDC complexity.

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Recommended implementation pattern

For most mobile apps:

1. Use provider SDK or browser-based OAuth with PKCE
2. Send auth code / ID token to your backend
3. Verify on backend
4. Issue your own app JWT/session
5. Store tokens securely on device

Use:

• Keychain on iOS
• Keystore / EncryptedSharedPreferences on Android

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If you want, I can give you:

• a step-by-step setup for Google login
• an iOS/Android code example
• or a backend flow diagram for social login