JWT Decoder

Decode JWT tokens and inspect header, payload, and signature. No server needed.

Header

{
  "alg": "HS256",
  "typ": "JWT"
}

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9

Payload

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022
}

eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ

Signature

SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c — HMACSHA256(base64UrlEncode(header) + '.' + base64UrlEncode(payload), secret)

Frequently Asked Questions

Is my JWT sent anywhere?

No — all decoding happens in your browser. Your tokens never leave your computer.

What is a JWT?

JSON Web Token — a compact, URL-safe means of representing claims between two parties. Commonly used for authentication.

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