What is JWT Decoder?
JWT Decoder is a free online tool that decodes a JSON Web Token and shows its header and payload claims (exp, iat, sub, roles) as readable JSON. It decodes only and never claims the signature is valid.
Decode JWTs online to inspect claims. This tool does not verify signatures — use it for debugging only. Free JWT decoder on Fah Swe Tools.
Key features
- Decodes header and payload
- Accepts tokens with a Bearer prefix
- Readable JSON claims
- Nothing is stored
Popular uses
- Debug login and API authentication
- Check token expiry (exp)
- Inspect roles and scopes
Also known as: JWT Decode Online, JSON Web Token Viewer, JWT Parser.
How it works
- Paste a JWT (optionally with Bearer prefix).
- Inspect header claims and payload JSON.
- Remember: this does not prove the token is authentic.
FAQ
Do you verify signatures?
No. Verification would require secrets/keys and could be misread as a trust oracle. This tool only decodes.
Stored?
Never — processed in memory for the request.
Can anyone read a JWT?
Yes. The payload is only Base64URL-encoded, not encrypted. Never put secrets in a JWT.
How do I check when a JWT expires?
Decode it and read the exp claim — a Unix timestamp in seconds.