JWT Decoder

Decode a JSON Web Token header and payload locally and read its expiry as a real date.

How to use

Paste a JWT and press Decode. The header and payload are base64url-decoded and pretty-printed, and the exp, iat and nbf claims are shown as UTC times with a validity note.

FAQ

The signature is never verified, because verification needs the signing secret or public key, which never leaves your server. This tool only shows what the token claims, which is enough to debug expiry and claim mistakes.

Privacy: every calculation runs inside your browser. Your files and text never leave your device.