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JWT Decoder

Decode and inspect JSON Web Tokens (JWT) to view header, payload, and signature information.

About JWT

JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.

Structure of a JWT

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

  1. Header - Contains the token type and the signing algorithm used
  2. Payload - Contains the claims or the data being transmitted
  3. Signature - Used to verify that the sender of the JWT is who it says it is

Common Claims

  • iss (Issuer): Identifies who issued the token
  • sub (Subject): Identifies the subject of the token
  • aud (Audience): Identifies the recipients of the token
  • exp (Expiration Time): Identifies when the token expires
  • nbf (Not Before): Identifies when the token starts being valid
  • iat (Issued At): Identifies when the token was issued
  • jti (JWT ID): Provides a unique identifier for the token

Note: This tool only decodes JWT tokens and displays their content. It doesn't validate signatures cryptographically. For security-sensitive applications, always verify JWT signatures using proper libraries.

How to Use

  1. Paste your JWT token into the input area above.
  2. View the decoded Header, Payload, and Signature by switching tabs.
  3. Click Copy to copy any part of the token or the whole token.
  4. Use Load Sample to try with a sample JWT, or Clear to reset.

Frequently Asked Questions (FAQ)

What is a JWT?

JWT (JSON Web Token) is a compact, URL-safe means of representing claims to be transferred between two parties. It is commonly used for authentication and information exchange.

Is my data secure?

All decoding is done locally in your browser. No data is sent to any server.

Does this tool verify the signature?

No. This tool only decodes the token and does not verify its signature. For security-critical applications, always verify JWTs on the server using trusted libraries.

Can I use this for sensitive tokens?

While your data is not sent anywhere, never share sensitive tokens with untrusted tools or people.

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