JWT Analyzer & Security Checker

This JWT Analyzer and Security Checker offers a robust, client-side solution for inspecting JSON Web Tokens. Key features include: • Decode and verify JWTs locally • Comprehensive security risk scoring (0-100) • Signature validation for HS256/384/512, RS256/384/512, PS256/384/512 • Detection of dangerous 'none' algorithm and weak secrets • Timeline analysis for 'exp', 'nbf', 'iat' claims • 100% offline operation, ensuring data privacy This tool meticulously examines JWT structures for potential vulnerabilities and best practice adherence. It goes beyond simple decoding by performing detailed checks on signatures, algorithms, and claims, including `exp`, `nbf`, and `iat` timestamps. It also identifies security misconfigurations such as missing `iss` or `aud` claims, the presence of sensitive data in the payload, and potential Key ID confusion attacks. Through its integrated risk scoring system, users gain immediate insights into a token's security posture. All processing occurs entirely within your browser using the native Web Crypto API, meaning sensitive token data never leaves your device. This secure approach makes it an ideal resource for developers, security researchers, and quality assurance teams who need to validate and audit JWTs without compromising data confidentiality. It supports exporting detailed reports in JSON, Markdown, and PDF formats, facilitating documentation and collaboration. Built for those who prioritize security and privacy, this analyzer is an invaluable asset for anyone working with token-based authentication systems.