JWT Decoder

Decode and verify JSON Web Tokens (JWT). Free online JWT decoder with header and payload inspection.

About JWT Decoder

JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. This tool decodes JWT tokens and displays the header and payload in a readable format.

Features

  • Decode JWT header and payload
  • Display token algorithm and type
  • Show expiration and issued-at timestamps
  • Format JSON output for readability
  • Client-side decoding - your tokens never leave your browser

Security Note

This tool only decodes JWT tokens - it does not verify signatures. JWT tokens are encoded, not encrypted, so the header and payload can be read by anyone. Never put sensitive information in a JWT without proper encryption.

JWT Structure

A JWT consists of three parts separated by dots (.):

  • Header: Contains token type and signing algorithm
  • Payload: Contains claims (user data, expiration, etc.)
  • Signature: Used to verify the token hasn't been tampered with