Developer

JWT Decoder

Decode and inspect JSON Web Tokens

JWT Token

Headerclick to copy

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

Payloadclick to copy

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022,
  "exp": 1999999999
}

Signatureclick to copy

SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

About JWT Decoder

The JWT Decoder decodes and inspects JSON Web Tokens, showing the header, payload, and signature. It runs entirely in your browser with no data sent to any server. This free tool is essential for developers debugging authentication flows, API tokens, and session management.

Frequently Asked Questions

How do I decode a JWT?

Paste your JSON Web Token into the input field and the tool will instantly decode it, displaying the header, payload, and signature in a readable format. You can inspect claims like expiration time, issuer, and custom fields.

Is my JWT token sent to a server?

No, the decoding happens entirely in your browser. Your JWT is never transmitted to any server, which is important since tokens often contain sensitive authentication data and user information.

Does the tool verify the JWT signature?

The tool decodes and displays the JWT contents including the header, payload, and signature. It shows the algorithm used and the claims within the token. Signature verification requires the secret key, so the tool focuses on inspecting and understanding the token structure.