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JWT Decoder

Paste a JWT to see its decoded header and payload, plus whether it's expired — nothing is verified or sent anywhere.

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How to use

  1. Paste a JWT (three dot-separated parts).
  2. View the decoded header and payload as formatted JSON.
  3. Check the expiry banner to see if the token is still valid.
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Frequently asked questions

Does this verify the signature?

No. This tool only decodes the header and payload, which are base64url-encoded but not encrypted. Verifying the signature would require the secret or public key, which never leaves your server.

Is my token uploaded anywhere?

No. Decoding happens entirely in your browser — the token is never transmitted.

Why did decoding fail?

A JWT must have exactly three dot-separated, base64url-encoded parts. Make sure you copied the full token.

About this tool

JWT Decoder is a free, browser-based tool from Tools Platform. It runs entirely on your device — your data is never uploaded to a server, so it stays completely private. There are no accounts, no watermarks, and no limits. Paste a JWT to see its decoded header and payload, plus whether it's expired — nothing is verified or sent anywhere.