Noviilo

JWT Decoder

Runs locally

Paste a JSON Web Token to view its decoded header and payload. This tool decodes JWT contents — it does not verify the token signature.

This tool decodes JWT contents. It does not verify the token signature.
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Header

Your data is processed locally in your browser and is not uploaded.

Learn more about this tool⌄

How it works

The token is split on its three segments; the header and payload segments are Base64URL-decoded and parsed as JSON.

Common use cases

  • Debugging authentication issues
  • Inspecting claims during development

Frequently asked questions

Does this verify the signature?
No. It only decodes the header and payload. Signature verification is intentionally not performed.
Is my token sent anywhere?
No. JWTs may contain sensitive data, so decoding happens only in memory in your browser.

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