What should I use for Google, Apple, and Microsoft login in a SaaS app?

For a SaaS app, the usual recommendation is:

• Use OAuth 2.0 + OpenID Connect (OIDC) for Google, Apple, and Microsoft login
• Prefer a single identity broker / auth provider rather than wiring each provider directly into every app if you want less complexity

Best practical options

Option 1: Use a third-party auth platform

Good if you want to move fast and support multiple login providers cleanly.

Examples:

• Auth0
• Clerk
• Firebase Auth
• Supabase Auth
• AWS Cognito
• WorkOS (especially good if you’ll also need enterprise SSO later)

Why:

• Handles provider-specific quirks
• Gives you one normalized user identity
• Easier account linking
• Less security footguns
• Faster to maintain

Option 2: Implement OAuth/OIDC yourself

Good if you want full control and can handle the complexity.

Use:

• Google: OpenID Connect
• Microsoft: OpenID Connect via Microsoft Identity Platform / Entra ID
• Apple: “Sign in with Apple” using Apple’s OAuth-style flow with OIDC-like identity token verification

You’d typically:

1. Redirect user to provider
2. Receive authorization code
3. Exchange code on backend
4. Verify ID token
5. Create/link your internal user
6. Issue your own session/JWT

Important product choice: use email as the account key carefully

Don’t rely only on email as a unique identity across providers.

Why:

• Same email can appear via different providers
• Apple may relay emails
• Microsoft/Google accounts can change

Better:

• Use the provider’s stable subject identifier (sub) + provider name
• Link multiple providers to one internal user record

What I’d recommend for most SaaS apps

If you want fastest and safest:

• Auth0 or Clerk for consumer/workflow-heavy SaaS
• WorkOS if enterprise SSO is likely
• Firebase Auth if you’re already in the Firebase ecosystem

If you’re building your own backend/auth layer:

• Use OIDC
• Support:
  • Google
  • Microsoft Entra ID
  • Sign in with Apple
• Store:
  • internal user id
  • provider
  • provider subject id
  • verified email
  • linked identities

Special notes by provider

Google

• Straightforward OIDC
• Usually easiest to integrate

Microsoft

• Use the Microsoft identity platform (Azure AD / Entra ID)
• Good for both consumer Microsoft accounts and work/school accounts
• If targeting businesses, be careful to support tenant-specific org logins

Apple

• Required if you offer other social logins in iOS apps in certain cases
• Can return hidden relay email
• Name is often only provided on first consent
• Account linking logic matters a lot here

Short answer

Use OpenID Connect for all three, ideally through an auth provider like Auth0 or Clerk unless you specifically want to build and maintain the auth layer yourself.

If you want, I can also recommend the best choice based on your stack:

• React / Next.js
• mobile app
• backend language
• B2C vs B2B SaaS