How to Implement OAuth 2.0
Add OAuth authentication with Google, GitHub, and other providers for social sign-in.
What You'll Learn
This intermediate-level guide walks you through how to implement oauth 2.0 step by step. Estimated time: 10 min.
Step 1: Understand OAuth flow
Learn the Authorization Code flow with PKCE — the recommended OAuth pattern for web applications.
Step 2: Register with providers
Create OAuth apps on Google Cloud, GitHub, and other platforms to get client credentials.
Step 3: Implement the auth flow
Build the redirect, callback, and token exchange endpoints for your application.
Step 4: Store and manage tokens
Securely store access and refresh tokens, implement token rotation and expiration handling.
Step 5: Handle account linking
Connect OAuth accounts to existing users and handle cases where users sign in with different providers.
Frequently Asked Questions
Which OAuth providers should I support?▾
Start with Google (largest reach) and GitHub (developer audiences). Add Apple for iOS apps. More providers add complexity for diminishing returns.
Should I use a library or build from scratch?▾
Use NextAuth.js, Passport.js, or Clerk — OAuth has many security subtleties that libraries handle correctly.
How do I handle account linking?▾
Match by verified email address when possible. If emails don't match, let users manually link accounts from their settings page.