OAuth or JWT? Everything Developers Need to Know in 2025

https://www.nilebits.com/blog/2025/05/oauth-jwt-everything-need-know-2025/
In contemporary software development, authorization and authentication are essential elements. OAuth and JWT (JSON Web Tokens) are two of the most widely used protocols and standards available to developers today. Despite their frequent usage together, they have distinct functions and cannot be substituted for one another. This article gives a thorough side-by-side analysis of OAuth and JWT, explaining how each functions, when to use it, and why it’s important for contemporary application security.

Whether you’re developing a microservices architecture, a mobile backend, or a SaaS product, understanding the key differences and practical implementations of OAuth and JWT will help you design more secure and scalable systems.

What is OAuth?
OAuth (Open Authorization) is an open standard protocol for authorization, commonly used to grant third-party applications delegated access to resources without exposing user credentials.

Key Features
Delegated access (authorization without sharing passwords)
Token-based access (Access Tokens)
Supports multiple grant types (Authorization Code, Client Credentials, Password, etc.)
Often used in conjunction with OpenID Connect for authentication
Common Use Case
Allowing a user to log in to your application using their Google or Facebook account.

What is JWT?
JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. It is commonly used for authentication and information exchange.

Key Features
Self-contained and stateless
Base64-encoded JSON object with a signature
Supports HMAC or RSA encryption
Commonly used in stateless authentication mechanisms
Common Use Case
Storing user session data in a signed token to avoid database lookups for each request.

OAuth and JWT: Are They the Same?
No. OAuth is a protocol, and JWT is a token format.

OAuth can use JWT as the format for access tokens, but it doesn’t have to. Similarly, JWTs can be used independently from OAuth for custom authentication systems.

When to Use OAuth
Use OAuth when:

You need delegated authorization
You’re exposing APIs to third-party developers
You require scope-based access to resources
You need to separate authentication (OpenID Connect) and authorization
When to Use JWT
Use JWT when:

You want stateless session management
You want to embed user claims directly in a token
You need fast, scalable authentication
You’re implementing Single Sign-On (SSO)
OAuth vs. JWT: Tabular Comparison
Feature OAuth JWT
Definition Authorization protocol Token format for authentication
Purpose Delegated access to APIs Transmitting identity and claims
Stateless Can be stateful or stateless Stateless
Token Format Varies (can be JWT, opaque, etc.) Always JWT format
Used For Authorization Authentication and Information exchange
Token Storage Server or client Client
Revocation Requires state (e.g., token blacklist) Difficult (requires token expiration)
OAuth with JWT: How They Work Together
In most modern systems, OAuth 2.0 issues JWTs as access tokens. This combines the delegation power of OAuth with the stateless nature of JWT.

Example Flow:
User logs in via Google (OAuth)
Google issues an access token (JWT)
Your app validates and parses the JWT
User is granted access based on the token’s claims
Real-World Example: Using OAuth with JWT in Node.js
Here’s a basic example using Node.js, Express, and passport.js with Google OAuth and JWT.

1. Install Required Packages

npm install express passport passport-google-oauth20 jsonwebtoken dotenv

1. OAuth Strategy Setup

const passport = require('passport');
const GoogleStrategy = require('passport-google-oauth20').Strategy;
const jwt = require('jsonwebtoken');

passport.use(new GoogleStrategy({
  clientID: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  callbackURL: "/auth/google/callback"
}, (accessToken, refreshToken, profile, done) => {
  const token = jwt.sign({
    id: profile.id,
    name: profile.displayName
  }, process.env.JWT_SECRET, { expiresIn: '1h' });

  return done(null, token);
}));

​

1. Express App Integration

const express = require('express');
const passport = require('passport');
require('./auth');

const app = express();

app.get('/auth/google', passport.authenticate('google', {
  scope: ['profile']
}));

app.get('/auth/google/callback', 
  passport.authenticate('google', { session: false }),
  (req, res) => {
    res.send(`Your token: ${req.user}`);
  }
);

app.listen(3000, () => console.log('Server running on http://localhost:3000'));

JWT Verification in API Gateway

const jwt = require('jsonwebtoken');

function verifyJWT(req, res, next) {
  const token = req.headers.authorization?.split(' ')[1];
  if (!token) return res.sendStatus(403);

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    req.user = decoded;
    next();
  } catch {
    res.sendStatus(401);
  }
}

​Security Considerations
• JWT
o Always use HTTPS to prevent token interception
o Set short expiration times
o Avoid storing sensitive data in the token
• OAuth
o Always validate redirect URIs
o Implement proper token revocation
o Consider using PKCE for public clients
References
• The Ultimate Guide to Implementing Authentication in JavaScript Applications
• OAuth 2.0 – RFC 6749
• JWT.io – Introduction & Debugger
• OpenID Connect Specification
• Auth0 – JWT vs. OAuth

https://www.nilebits.com/blog/2025/05/oauth-jwt-everything-need-know-2025/