JWT Decoder

Your token never leaves your browser. All decoding is done locally.
JWT Token

About this tool

Paste a JWT token to instantly decode and inspect its header, payload, and signature. Timestamps (exp, iat, nbf) are converted to human-readable dates. Expired tokens are flagged. Your token is never sent anywhere.

Understanding JSON Web Tokens

A JWT consists of three Base64URL-encoded parts separated by dots: header (algorithm and type), payload (claims like subject, expiration, and custom data), and signature (cryptographic verification). JWTs are widely used for authentication and API authorization.

  • Header decoding (algorithm, type)
  • Payload inspection with formatted JSON
  • Human-readable timestamps
  • Expiration detection
  • Color-coded sections (header, payload, signature)
  • Copy individual sections
  • Example token for testing
  • Privacy-first: nothing leaves your browser

100% free. No signup. No data collected anywhere.