JWT Token Decoder
Paste a JSON Web Token to see what is inside it: the header and payload are decoded into readable JSON, and common claims are explained with human-readable dates. This tool is 100 percent client-side and does not verify signatures — it only decodes.
Decode a token
Header
Payload
Signature
Claims table
| Claim | Value | Meaning |
|---|
How to use
- Paste the full token (three parts separated by dots) into the text box above.
- Click "Decode token" — or click "Load sample token" first to try the tool with a real example.
- Read the header and payload as highlighted JSON, and check the claims table for expiry dates and status.
- Use the copy buttons to copy the header JSON, payload JSON or signature separately.
- Remember: this tool decodes only. To check that a token is trusted, verify its signature on your own server with the correct secret or key.
Frequently asked questions
What does the JWT Token Decoder do?
It splits a JSON Web Token into header, payload and signature, decodes the base64url parts into readable JSON with syntax highlighting, and explains the claims in a table.
Does it verify the token signature?
No. The tool does not verify signatures and needs no secret — it only decodes and displays what the token contains.
Which claims are explained?
iss, sub, aud, exp, nbf and iat, with human-readable dates and an expired or valid status compared to the current time.
Is my token sent to a server?
No. Decoding happens fully in your browser; nothing leaves your device.
What happens with an invalid token?
The tool shows a clear error that explains whether the format is wrong or one of the parts cannot be decoded as JSON.