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🔑 JWT Decoder
Decode a JSON Web Token's header and payload instantly — no signature check, nothing uploaded.
About this JWT Decoder
A JSON Web Token is three Base64Url-encoded parts joined by dots: a header describing the token, a payload carrying claims like user id and expiry, and a signature. This decoder unpacks the header and payload into readable JSON and converts the standard exp and iat timestamps into dates. It runs entirely in your browser — important, because tokens are credentials and should never be pasted into unknown servers.
How to use it
- Copy the full JWT from your app, API response or browser storage.
- Paste it into the box and click Decode token.
- Read the header and payload JSON, plus the human-readable expiry.
- Remember: decoding shows the contents, but does not prove the token is genuine.
Example
Decoding the classic demo token beginning 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9' reveals a payload with sub 1234567890, name 'John Doe' and an iat timestamp.
Frequently asked questions
Does this verify the signature?
No. Anyone can decode a JWT — verification needs the issuer's secret or public key on a server. Never trust a token just because it decodes.
Is it safe to paste a real token?
The decoding happens locally in this page; nothing is sent over the network. Even so, treat live tokens like passwords and avoid sharing them.
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