OAuth vs JWT - What's the Difference in Web Authentication & Authorization?

• OAuth vs JWT: What's the Difference in Web Authentication & Authorization?
  • What is OAuth?
  • What is JWT?
  • OAuth vs JWT: Key Differences
  • Can OAuth and JWT Work Together?
  • When to Use OAuth vs JWT
  • Conclusion

OAuth vs JWT: What's the Difference in Web Authentication & Authorization?

When building secure web applications, two terms you'll frequently encounter are OAuth and JWT (JSON Web Tokens). While they're often used together, they serve different purposes. In this post, we'll break down the key differences between OAuth and JWT, how they work, and when to use them in your app's security flow.

What is OAuth?

OAuth is an open-standard protocol used for authorization, allowing apps to access user data on another service without exposing user credentials.

🔐 Key Features:

• Delegation of access (not authentication itself)
• Used for third-party app access (e.g., "Login with Google")
• Issues access tokens (commonly in JWT format)
• Requires a trusted authorization server

📌 Example Use Case:

A user logs into your app using Google. Instead of storing or requesting their Google credentials, your app uses OAuth to get a temporary access token that permits limited access (like reading email or calendar events).

What is JWT?

JWT (JSON Web Token) is a compact, URL-safe token format used for authentication and secure data exchange.

🔐 Key Features:

• Stateless and self-contained
• Digitally signed (often with HMAC or RSA)
• Encodes user identity and claims (roles, permissions, etc.)
• Ideal for REST APIs

📌 Example Use Case:

After logging in, your server generates a JWT with the user's ID and roles, signs it, and sends it to the client. The client includes this token in headers for protected routes, and the server verifies the token signature without a database call.

OAuth vs JWT: Key Differences

Can OAuth and JWT Work Together?

Yes — and they often do. In many implementations, OAuth uses JWT as the format for access tokens. OAuth handles authorization, while JWT carries the actual identity and permission data.

When to Use OAuth vs JWT

• ✅ Use OAuth when you're allowing third-party apps to access your data or services on behalf of the user.
• ✅ Use JWT when you want to authenticate users and pass secure data between frontend and backend or across services in a stateless way.

Conclusion

Understanding OAuth and JWT is essential for implementing modern, secure authentication and authorization systems. OAuth is a delegation protocol, while JWT is a token format — often used together but not interchangeable. Choose the right tool based on whether you're dealing with user delegation or stateless authentication.