JWT Decoder

A JWT (JSON Web Token) is a compact token format used for authentication and information exchange. This tool decodes JWT tokens to reveal the header, payload, and signature components in a readable format.

Yes, all decoding happens locally in your browser. Your token is never sent to any server. However, for production tokens containing sensitive claims, always use caution and avoid sharing tokens publicly.

The tool decodes and displays the token structure including the algorithm used. Full signature verification requires the secret key or public key which is not provided to maintain security best practices.

You can see the header (algorithm and token type), payload (claims like issuer, expiration, subject, and custom data), and the signature. The payload often contains user IDs, roles, and expiration timestamps.

Yes, the decoded payload shows the expiration claim (exp) as a Unix timestamp. The tool helps you easily identify when a token was issued and when it expires, useful for debugging authentication issues.