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JWT Decoder

Decode JWT headers/payloads and check expiry locally.

Free, no uploads, no sign-up. Runs 100% in your browser.

How JWT Decoder works

JWT Decoder runs entirely in your browser. Decode JWT headers/payloads and check expiry locally. Under the hood it uses Web Crypto API (the browser’s built-in, hardware-accelerated cryptography). Your files are read into this tab’s memory, processed on your own CPU, and handed back to you as a download. Nothing is sent to a server.

How to use JWT Decoder

1. Open JWT Decoder and paste or type your input.
2. Results update instantly as you type.
3. Tweak options such as format, indentation or algorithm.
4. Copy the output or download it as a file.

Tips

• Decoding never verifies the signature unless you provide the secret/key. Never trust an unverified token.
• Safe for production tokens: nothing is sent anywhere.

JWT Decoder FAQ

Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

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