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JWT Decoder

Decode JWT headers and payloads in the browser to inspect token claims, expiration times, issuers, and scopes without sending tokens to a server.

How to Use

  1. Paste your JWT token
  2. Click Decode JWT
  3. View the decoded header, payload, and signature
  4. Copy the formatted or generated result directly to your clipboard.
  5. Use the result in your application, configuration, or documentation safely.

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

A JWT contains three parts: a Header (algorithm and token type), a Payload (claims/data), and a Signature (verification).
This tool decodes and displays the JWT contents but does not verify the cryptographic signature.
Yes, all processing happens locally in your browser. Your token is never sent to any server.
No. All operations are processed entirely inside your browser's local sandbox using client-side APIs (like WebAssembly, pdf-lib, or HTML5 Canvas). Your files and data never leave your device.
The tool is completely free with no usage limits. However, since processing occurs in your browser's memory, we recommend keeping file sizes under 50MB (especially for heavy files like PDFs or videos) to ensure stability.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.
Yes. Once the page and its local library dependencies are loaded in your browser, the conversion logic runs completely offline without needing an active internet connection.

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