JWT Decoder

About JWT Decoder

Our free JWT decoder helps developers and security professionals analyze JSON Web Tokens instantly. Decode the header, payload, and signature sections with automatic timestamp conversion and expiration status checking. All processing happens in your browser—no data is sent to any server.

What is JWT?

JWT (JSON Web Token) is a compact, URL-safe token format used for stateless authentication and information exchange. It consists of three parts separated by dots: the header (token type and signing algorithm), the payload (claims and data), and the signature (verification).

Key Features

• Decode Header: View token type, algorithm, and metadata
• Decode Payload: See all claims and user information
• Timestamp Conversion: Automatically convert Unix timestamps to human-readable dates
• Expiration Status: Check if token is expired or valid
• Color-Coded Sections: Header in blue, payload in green, signature in red
• 100% Private: All decoding happens locally in your browser

JWT Structure Explained

• Header: Contains the token type (JWT) and the hashing algorithm (HS256, RS256, etc.)
• Payload: Contains claims—statements about the entity and additional metadata
• Signature: Ensures token integrity and authenticity using the algorithm specified in header

Common JWT Claims

• iss: Issuer of the token
• sub: Subject—the user ID
• aud: Audience—intended recipient
• exp: Expiration time (Unix timestamp)
• iat: Issued at time (Unix timestamp)
• nbf: Not before time (Unix timestamp)

How to Decode a JWT

Simply copy your JWT token and paste it into the input field. Click "Decode" and the tool will instantly display the header, payload, and signature in separate sections. Timestamps will be converted to readable dates, and you'll see the expiration status at a glance. This is useful for debugging authentication issues, verifying token contents, and understanding token claims.

Security Note

Decoding a JWT does not verify its signature. This tool decodes tokens to show you what information they contain, but signature verification requires the secret key. Never share JWTs containing sensitive information, and always use HTTPS for token transmission.