About The JWT Decoder

JWT Decoder reads a JSON Web Token and displays the decoded header and payload. It is meant for inspecting claims, debugging authentication flows, and checking token shape quickly.

Decoding happens locally in your browser and does not verify trust. Use JWT Verifier when you need to validate a signature before trusting claims.

How to Decode JWTs Online

1. Paste a complete JWT into the token field.
2. Click Decode.
3. Review the header algorithm and payload claims such as issuer, audience, subject, issued-at, and expiry.

Choosing Options Correctly

This decoder has no verification options. Treat decoded claims as readable data only until the token signature has been verified elsewhere.

Common Use Cases

• Debugging auth middleware and identity-provider claims.
• Checking malformed tokens during integration work.
• Inspecting time-based claims while troubleshooting sessions.

Quick FAQ

Does decoding prove the token is valid?
No. Decoding only reads the header and payload. Signature, issuer, audience, expiry, and algorithm must still be verified.

Why did decoding fail?
The token may be malformed, missing three parts, use invalid Base64URL, or contain non-JSON header or payload data.

Should I paste production tokens?
Avoid pasting live tokens. JWTs often contain claims or bearer access that should be treated as sensitive.

What should I inspect first?
Check algorithm, key ID, issuer, audience, subject, issued-at, not-before, and expiry claims before trusting the token.