JWT Decoder

A JWT (JSON Web Token) decoder is a tool that decodes and inspects JWT tokens to view their structure and contents. JWTs are used for authentication and authorization in modern web applications, and understanding their structure is essential for developers working with APIs and authentication systems.

Our free JWT decoder allows you to decode JWT tokens and view the header, payload, and signature components. All processing happens in your browser, ensuring your tokens remain private and secure.

Why Decode JWTs?

• Debugging: Inspect token contents during development
• Learning: Understand JWT structure and claims
• Verification: Verify token payload and expiration
• Troubleshooting: Debug authentication issues
• Security: Review token claims and permissions

JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. JWTs are commonly used for authentication and authorization in web applications.

JWT Structure:

• Header - Contains token type and signing algorithm
• Payload - Contains claims (user data, expiration, etc.)
• Signature - Used to verify the token hasn't been tampered with

Common Claims:

• sub - Subject (user ID)
• iat - Issued at (timestamp)
• exp - Expiration time (timestamp)
• iss - Issuer
• aud - Audience