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🔓 JWT Decoder

Decode and inspect JSON Web Tokens (JWT) to view header, payload, and signature

Understanding JWT Tokens

What is a JWT?

A JWT (JSON Web Token) is a compact, URL-safe token format used for securely transmitting information between parties. JWTs are commonly used for authentication and information exchange in web applications, APIs, and microservices.

JWT Structure

A JWT consists of three Base64-URL encoded parts separated by dots: Header (algorithm and token type), Payload (claims and data), and Signature (verification component). Each part serves a specific purpose in the token's security and functionality.

Security Considerations

While JWTs are encoded, they are not encrypted - anyone can decode them to read the contents. Never include sensitive data like passwords in JWT payloads. Always validate signatures server-side and use HTTPS to prevent token interception.

How to Use This Tool

  1. Paste your JWT token into the input field above (you can use the sample token provided or your own)
  2. The tool will automatically decode and display the header, payload, and signature as you type
  3. Review the decoded header (algorithm and type), payload (claims and data), and signature sections
  4. View token information including algorithm, issued time (iat), and expiration (exp) with expiry status
  5. Use the Copy buttons to copy individual sections (header, payload, or signature) to your clipboard
Note: This tool only decodes JWTs to display their contents. It does not validate signatures. Never share or decode sensitive production tokens on untrusted sites.

Frequently Asked Questions

What is a JWT token?

A JWT (JSON Web Token) is a compact, URL-safe token format used for securely transmitting information between parties. It consists of three parts: header, payload, and signature, separated by dots.

Does this tool validate JWT signatures?

No, this tool only decodes JWTs to display their contents. It does not validate signatures or verify token authenticity. Signature validation requires the secret key and should be done server-side.

Is it safe to decode my JWT here?

All decoding happens entirely in your browser - your JWT never leaves your device or gets sent to our servers. However, avoid decoding tokens with sensitive production data on any public site as a security best practice.

Is this tool free to use?

Yes, this JWT decoder is completely free to use with no registration or limitations.

Does this work on mobile devices?

Yes, this tool is fully responsive and works on all mobile devices, tablets, and desktop computers.