JWT Learning Path

Structured JWT learning path. Master token decoding, validation, OAuth integration, and security best practices step by step.

Learning Steps

Step 1

Understand JWT Structure

Learn header, payload, signature. Decode your first token.

Step 2

Authentication Flow

How JWT authentication works in APIs and web apps.

Step 3

Validate & Debug Tokens

Verify signatures, check claims, debug issues.

Step 4

Choose the Right Algorithm

HS256 vs RS256 and when to use JWKS.

Step 5

OAuth & Production Security

OAuth integration, refresh tokens, and security hardening.

Common Mistakes

  • Decoding without verifying signature
  • Storing JWTs in localStorage
  • Using weak HS256 secrets
  • Ignoring exp, iss, and aud validation
  • Accepting alg: none

Real-World Attack Scenarios

XSS Token Theft

Mitigation: httpOnly cookies, CSP, short-lived tokens

Algorithm Confusion

Mitigation: Whitelist algorithms, never use public key as HMAC secret

Token Replay

Mitigation: Short exp, jti claim with revocation list