JWT Decoder
Decode and inspect JSON Web Tokens to view header, payload, and check expiration.
Enter JWT Token
Header
Decoded header will appear here
Payload
Decoded payload will appear here
Privacy First: All decoding happens locally in your browser. Your tokens never leave your device.
What is a JWT?
JSON Web Token (JWT) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. JWTs are commonly used for authentication and authorization in web applications. They consist of three parts: header, payload, and signature.
JWT Structure
- Header: Contains token type and signing algorithm (e.g., HS256, RS256)
- Payload: Contains claims - user data and metadata (iss, sub, exp, iat, etc.)
- Signature: Verifies the token hasn't been tampered with
Common JWT Claims
- iss: Issuer - who created the token
- sub: Subject - who the token is about
- exp: Expiration time (Unix timestamp)
- iat: Issued at time
- aud: Audience - intended recipients
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