JWT Decoder
Decode JWT header and payload with expiry check.
⚿JWT Decoder
All processing happens locallyWhat this tool does
JWT Decoder is a local JSON Web Token debugging tool, decoding runs in the browser, so tokens never reach a server, making production credentials safe to inspect.
Paste the full token (xxx.yyy.zzz) to see the decoded header and payload. The signature can only be inspected for format, not verified, since that needs the server secret.
How to use it
- Paste or type your content into the input field at the top, or press the sample button to load demo data.
- Adjust the options below the input, such as output format, separators, letter case or precision.
- Press the main button to run the conversion. Results appear instantly in the output panel without a page reload.
- When the result looks right, use the copy button in the corner, or download it as a local file.
Tips and notes
Clean up stray spaces and line breaks before pasting for more accurate results.
FAQ
No. Verification needs the server key, which a front-end cannot hold; this tool decodes and checks structure only.
JWT payloads are Base64 encoded rather than encrypted, so anyone holding the token can read them. Never put secrets in a payload.
The exp claim is a Unix timestamp in seconds; the tool compares it with the current time and shows remaining lifetime.
Yes. The tool is completely free with no usage limits, and you never need an account or a sign-in.
No. All processing runs locally in your browser, so the input never reaches a server and is never logged or stored.
Yes. The layout is mobile-first, so inputs and buttons stay comfortable on phones and tablets in both orientations.
Yes. A copy button in the output panel puts the result on your clipboard, and you can also download it as a text file.