Tutorial | Jwudtool

Learn how to decode, verify, and debug JSON Web Tokens using jwudtool. Perfect for developers and security testers. Introduction JSON Web Tokens (JWTs) are everywhere — from authentication flows to API authorization. But if you’ve ever tried to manually decode a JWT or debug a signature mismatch, you know it can get messy fast.

Happy debugging! This tutorial is for educational purposes only. Only test tokens you own or have permission to analyze. jwudtool tutorial

✗ Signature mismatch For RS256 tokens, use a public key: Learn how to decode, verify, and debug JSON

HEADER:

jwudtool verify --pubkey public.pem <token> Need to change a claim for testing? Clone and modify: Learn how to decode

💡 Tip: Use --pretty for colorized output. If you have the secret key ( mysecret ):