What is a Jwt?

A JWT Decoder parses JSON Web Tokens (JWTs) by splitting the Base64URL-encoded segments into their Header, Payload, and Signature components. It displays the decoded JSON with syntax highlighting, detects expiration timestamps, and validates whether the token is still active — all without sending your token to any server.

How to Use This Tool

  1. Paste your JWT token (starting with 'eyJ...') into the input field.
  2. The tool automatically decodes the Header, Payload, and Signature.
  3. View the algorithm and token type in the Header section.
  4. Inspect claims like 'exp', 'iat', 'sub' in the Payload section.
  5. Check the expiration status — the tool shows if the token is valid or expired.
  6. Copy any section with the built-in copy buttons.

Key Features

  • Instant JWT decoding with Base64URL parsing
  • Color-coded Header (red), Payload (purple), Signature (blue) sections
  • Automatic expiration detection with valid/expired status
  • Issued-at (iat) timestamp with relative time display
  • Smart extraction from cookies, Bearer headers, and raw strings
  • 100% client-side — tokens never leave your browser

Frequently Asked Questions

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