APIs
JWT Decoder
Decode a JSON Web Token to read its header and payload, including issued-at and expiration claims. Decoding does not verify that the token is authentic or secure.
Decoding a JWT does not verify that the token is authentic or secure. Signatures are not checked. Do not paste live production tokens if your policy forbids it — processing still happens locally.
How to use it
- Paste a JWT with three base64url segments separated by dots.
- Inspect the header (algorithm and type) and payload claims.
- Check issued-at and expiration against the current time.
- Copy individual JSON objects if you need them in a ticket or log.
Example
A token with exp in the past is marked expired. A token with nbf in the future is marked not yet valid. Signature bytes are shown as present or missing — they are not validated.
Privacy
Tokens never leave your browser. Do not paste production secrets into any online tool if your threat model forbids it; this decoder still processes data locally.
FAQ
Does decoding prove a JWT is valid?
No. Decoding a JWT does not verify that the token is authentic or secure. Signature verification requires the correct secret or public key and must happen on a trusted server.
Are tokens uploaded?
No. Base64url decoding runs in the browser. We recommend using sample or expired tokens when demonstrating the tool.
Which claims are interpreted?
The tool highlights exp, iat, nbf, iss, aud, and sub when present. Other claims are shown as raw JSON.
Next step
Need this wired into a real system?
Estimators and converters help you think. Delivery still needs contracts, environments, and an owner.