JWT Explainer
Decode and explain JWTs with security focus. Understand token claims and expiration.
🔒 All decoding happens locally in your browser. Your token is never sent to any server.
Security Analysis
Paste a JWT above to decode and analyze
Claims Explained
⚠️ Important Notes
- This tool decodes JWTs but does not verify signatures
- Signature verification requires the secret/public key and should happen server-side
- Never trust a JWT's claims without proper server-side verification
How to Use JWT Explainer
- Paste your JWT token
- View decoded header and payload
- Each claim is explained in plain English
- Security warnings are highlighted
About JWT Explainer
Decode and understand JSON Web Tokens with a security focus. See header, payload, and signature sections explained. Warns about expired tokens, weak algorithms, and security issues.
Frequently Asked Questions
Does this verify the signature?
No, this is a client-side decoder. Signature verification requires the secret key and should happen server-side.
What security issues are flagged?
Expired tokens, "none" algorithm, missing required claims, and tokens expiring soon.
Is it safe to paste my JWT here?
Yes, all decoding happens in your browser. Nothing is sent to any server.