I'm building a mobile app and want login plus social sign in, what auth should I use?

For a mobile app with email/password login + social sign-in, the usual best choice is OAuth 2.0 / OpenID Connect (OIDC) with a managed authentication provider or an auth backend.

Best option for most mobile apps

Use a provider like:

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

These give you:

• Email/password auth
• Google / Apple / Facebook / etc. sign-in
• Token handling
• Password reset / email verification
• User management
• MFA support in many cases

Recommended approach

For mobile, prefer:

• OpenID Connect (OIDC) for identity
• OAuth 2.0 Authorization Code Flow with PKCE for sign-in

This is the modern secure flow for native apps. Avoid embedding client secrets in the app.

What I’d recommend by scenario

If you want the fastest setup

• Firebase Auth
  • Easiest to integrate
  • Good for MVPs
  • Great mobile SDKs
  • Works well with Google/Apple sign-in

If you want more enterprise control

• Auth0 or AWS Cognito
  • Better if you need advanced rules, SSO, enterprise identity, or more customization

If you’re already using a backend/database

• Supabase Auth
  • Nice if you want auth tied closely to your backend and Postgres

Social sign-in notes

• If you target iOS, Sign in with Apple is often required if you offer other social logins.
• If you support Google login, also consider Apple login for iOS compliance/user preference.
• Don’t build social login yourself; let the provider handle OAuth flows.

Simple decision guide

• MVP / small app → Firebase Auth
• Custom enterprise needs → Auth0
• AWS stack → Cognito
• Postgres-first app → Supabase Auth

Security basics

• Use PKCE
• Use short-lived access tokens
• Store tokens securely:
  • iOS Keychain
  • Android Keystore / EncryptedSharedPreferences
• Prefer refresh tokens with rotation if supported
• Never ship secrets in the app

If you want, I can recommend the best auth provider based on your stack (Flutter / React Native / native iOS/Android / backend language / cloud).