JWT Decoder
Free online JWT decoder. Inspect the header and payload of any JSON Web Token instantly — fully client-side, so sensitive tokens never leave your browser.
How to use JWT Decoder
- 1
Paste your JWT (the full token with the two dots).
- 2
The header and payload are decoded and formatted instantly.
- 3
Check the expiry status — the tool compares exp with the current time.
- 4
Copy the decoded header or payload as needed.
Key features
Decodes header and payload instantly
Pretty-printed JSON for both parts
Highlights exp / iat / nbf claims
Expiry status indicator
Works fully offline in the browser
Copy any part in one click
JWT Decoder — FAQ
Yes — decoding happens entirely in your browser. Your token is never transmitted to any server, which is the point of a local decoder.
No. Signature verification requires the secret or public key, which this tool never asks for. It only decodes the (non-secret) header and payload.
The header describes the token itself (algorithm and type, e.g. HS256). The payload contains the claims — the actual data like user ID, expiry and issuer.
A JWT must have exactly three dot-separated parts with valid Base64Url encoding. Extra whitespace, line breaks or a malformed signature section cause invalid-format errors.
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