🔑 JWT Decoder
Decode JWT tokens to inspect header and payload. View claims, expiration, and issuer information — all in your browser, no upload.
About the JWT Decoder
This JWT decoder runs entirely in your browser. Paste a JSON Web Token, click Decode, and you can inspect the header, payload, and signature as well as common claims such as issuer, subject, audience, and expiration. Nothing is uploaded to a server — all decoding happens with JavaScript on your device.
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe token used to transmit claims between parties. It has three parts separated by dots: header.payload.signature. The header and payload are Base64URL-encoded JSON objects, while the signature is used to verify integrity.
Common claims decoded
- iss — Issuer of the token.
- sub — Subject (usually the user identifier).
- aud — Intended audience.
- exp — Expiration time (shown as a human-readable date).
- iat — Issued-at time.
- nbf — Not-before time.
Frequently asked questions
Does this verify the signature? No. This tool only decodes the header and payload for inspection. It does not validate the signature against a secret or public key.
Are expired tokens highlighted? Yes. If an exp claim is present and the token has expired, the expiration row is highlighted in red.
Is my token uploaded anywhere? No. Decoding is local. For sensitive tokens, prefer offline or self-hosted tools and review the source before use.