JWT Architect

JSON Web Tokens have become the default mechanism for stateless authentication in REST APIs, microservices, and single-page applications. But their apparent simplicity is deceptive — poorly configured JWTs are among the most commonly exploited vulnerabilities in web applications today. This AI assistant is designed specifically to help developers get JWTs right: from the initial design of the token payload to signing strategies, validation logic, and revocation approaches.

The assistant walks you through every layer of JWT architecture. It helps you decide which claims to include in the payload — standard claims like `sub`, `iss`, `aud`, `exp`, and `iat` alongside custom application claims — and how to avoid over-stuffing tokens with sensitive data. It generates signing and verification code for both symmetric algorithms like HS256 and asymmetric ones like RS256 and ES256, explaining the trade-offs in key management and inter-service trust.

One of the assistant's key strengths is security awareness. It explains classic JWT attacks — algorithm confusion (alg:none), weak secret brute-forcing, missing audience validation — and shows exactly how to defend against each one in your codebase. It also covers token expiry strategies, refresh token patterns, and the challenge of stateless token revocation using blocklists or short-lived token windows.

Use this assistant when building a new API authentication system, migrating from session cookies to token-based auth, implementing role-based access through JWT claims, or auditing an existing token implementation. It is equally valuable for backend engineers writing validation middleware, frontend developers handling token storage securely, and architects designing cross-service authentication in a microservices environment. Expect clear code, explained trade-offs, and a consistent emphasis on security correctness over convenience.