JWT Decoder

What is a JWT Token?

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. This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret (with the HMAC algorithm) or a public/private key pair using RSA or ECDSA.

JWT tokens are commonly used in modern web applications for authentication and information exchange. They consist of three parts separated by dots (.), which are Header, Payload, and Signature, making them easy to pass in HTTP environments.

JWT Token Structure

A JWT token consists of three Base64-URL encoded parts separated by dots:

• Header: Contains metadata about the token, including the signing algorithm and token type
• Payload: Contains the claims, which are statements about an entity and additional data
• Signature: Used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way

How to Use the JWT Decoder

Using our JWT decoder tool is simple and straightforward. Follow these easy steps to decode your JSON Web Tokens:

• Copy your JWT token from your application or authentication system
• Paste the complete JWT token into the input field above
• Click the "Decode JWT Token" button to process your token
• View the decoded header, payload, and signature information
• Analyze the token claims, expiration time, and other metadata

Key Features of Our JWT Decoder

• Instant Decoding: Real-time JWT token parsing and analysis
• Complete Analysis: View header, payload, and signature details
• Security First: All processing happens in your browser - no data sent to servers
• User-Friendly: Clean interface with formatted JSON output
• Mobile Responsive: Works perfectly on all devices and screen sizes
• Error Handling: Clear error messages for invalid tokens
• Copy-Paste Ready: Easy to copy decoded results for further use

Understanding JWT Claims

JWT claims are pieces of information asserted about a subject. Claims are name/value pairs that provide details about the token and the subject. There are three types of claims:

Registered Claims

These are predefined claims that provide useful, interoperable information:

• iss (Issuer): Identifies the principal that issued the JWT
• sub (Subject): Identifies the principal that is the subject of the JWT
• aud (Audience): Identifies the recipients that the JWT is intended for
• exp (Expiration Time): Identifies the expiration time after which the JWT must not be accepted
• iat (Issued At): Identifies the time at which the JWT was issued
• nbf (Not Before): Identifies the time before which the JWT must not be accepted

Security and Best Practices

When working with JWT tokens, it's important to follow security best practices:

• Always validate the token signature before trusting the payload
• Check the expiration time (exp) claim to ensure tokens haven't expired
• Verify the issuer (iss) and audience (aud) claims match expected values
• Use strong, secure secrets for HMAC algorithms
• Store tokens securely on the client side
• Implement proper token refresh mechanisms