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JWT

JWT Decoder

Decode and inspect JSON Web Tokens without sending them to a server

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What is JWT Decoder?

Decode JSON Web Tokens (JWT) instantly in your browser. Paste a JWT and see the decoded header, payload, and signature. The tool shows the algorithm used, all claims including expiration time, and whether the token is still valid. Perfect for debugging authentication flows, inspecting API tokens, and understanding JWT structure. Your tokens never leave your browser — everything is decoded locally.

How to Use JWT Decoder

  1. 1Paste your JWT token into the input field
  2. 2Click 'Decode' to parse the token
  3. 3Review the decoded header (algorithm, type) and payload (claims, expiration)
  4. 4Copy individual sections or check the token's expiration status

Frequently Asked Questions

A JSON Web Token (JWT) is a compact, URL-safe token format used for securely transmitting information between parties. It consists of three parts separated by dots: a header (algorithm and type), a payload (claims/data), and a signature. JWTs are commonly used for authentication and authorization in web applications.
Yes. This tool decodes JWTs entirely in your browser using JavaScript. The token is never sent to any server. However, remember that JWTs are only encoded (not encrypted), so anyone with the token can read its contents.
This tool decodes and displays the JWT contents but does not verify signatures, as that requires the secret key or public key used to sign the token. It is designed for inspection and debugging, not for security validation.
Common claims include: iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), iat (issued at), and jti (JWT ID). Custom claims can contain any application-specific data.

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