JWT Decoder
DeveloperNewPaste any JWT to instantly decode the header and payload. Explains common claims (iss, sub, exp), shows expiry countdown, and highlights the signature algorithm.
Frequently asked questions
How do I decode a JWT without a library?
Paste the full token into the input field and the header and payload segments decode instantly, with each claim like iss, sub, and exp explained next to its value and the signature segment shown separately.
Can this tool verify a JWT signature?
No, this tool decodes the header and payload only, since that requires no secret key. Verifying the signature requires the issuer's secret or public key and should be done server-side, never trust claims from an unverified token.
Is it safe to paste a production JWT into this decoder?
Decoding runs in your browser and the token is not sent anywhere, but a JWT payload is only base64url-encoded, not encrypted, so anyone with the token can already read its claims. Avoid pasting tokens containing secrets you would not want exposed elsewhere.
How can I tell when a JWT will expire?
The decoded payload highlights the exp claim and shows a live countdown or an 'expired X ago' indicator, so you can see at a glance whether the token is still valid without manually converting the Unix timestamp.