The JWT Decoder instantly decodes all three parts of a JWT Token (Header, Payload, Signature), auto-detects expiry, and explains standard claims — all processed locally in your browser.
Features
- 3-panel decode: Header (algorithm & type), Payload (claims), and Signature each displayed in separate panels with syntax highlighting.
- Expiry detection: Automatically checks the exp field — expired tokens show an orange warning, not-yet-valid tokens show a blue notice.
- Human-readable timestamps: iat, exp, and nbf Unix timestamps are automatically converted to readable date/time.
- Claims reference: Each claim in the Payload is explained below, including standard RFC 7519 claims like sub, iss, and aud.
- Quick example: Click "Load Example" to populate a sample JWT and see the decoder in action instantly.
- Per-panel copy: Each panel has its own copy button to copy Header, Payload, or Signature independently.
What is JWT?
- JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting claims between parties — commonly used for authentication and API authorization.
- A JWT consists of three Base64URL-encoded parts joined by dots: Header.Payload.Signature.
- ⚠ Note: JWT Payload is only Base64-encoded, not encrypted. Anyone can decode it — never store sensitive data (like passwords) in the Payload.
How to use?
