JWT Debugger

Welcome to the Professional JWT Debugger, a high-fidelity analysis tool designed for developers and security specialists working with JSON Web Tokens. JWT (RFC 7519) is the industry standard for securely transmitting information between parties as a JSON object, used extensively in authentication and authorization flows. However, since JWTs are Base64Url encoded, inspecting their contents or verifying their signatures manually can be a significant hurdle. Our tool provides an intuitive, structured interface to instantly decode any JWT into its three constituent parts: Header, Payload, and Signature. Beyond simple decoding, our debugger provides real-time validation of timestamps (such as iat, nbf, and exp) and allows you to verify the signature by providing a secret key or a public key (supporting HS256, RS256, and more). This is crucial for identifying misconfigurations or security vulnerabilities in your auth implementation. We prioritize technical privacy: all decoding and cryptographic verification happen locally within your web browser using JavaScript. Your sensitive tokens and signing keys are never transmitted to our servers, providing a "Zero-Knowledge" environment for debugging production data. Whether you are troubleshooting an "Unauthorized" API error or auditing your organization’s token-based security architecture, our JWT Debugger delivers the professional clarity and security you need.