JWT Authentication
Stateless API authentication, cryptographic token signing, refresh token rotation, and claims-based authorization.
1 / Stateless API Authentication
JWT (JSON Web Token) authentication was the stateless authentication mechanism across my backend services. In Trajectory and other Spring Boot applications, JWTs replaced server-side session storage — each request carried a cryptographically signed token containing user claims, eliminating the need for session lookup on every API call.
2 / Token Lifecycle
Implementing JWT properly required managing the complete token lifecycle: access token signing with appropriate expiration, refresh token rotation to prevent token reuse after compromise, and secure token storage on the client side. The refresh rotation pattern — issuing a new refresh token with each access token renewal and invalidating the old one — provided protection against token theft without requiring full re-authentication.
3 / Integration with Spring Security
In Spring Security, JWT validation was implemented as a custom filter in the security filter chain. The filter extracted the token from the Authorization header, validated the signature and expiration, and populated the SecurityContext with the authenticated user's claims. The ordering of this filter relative to other security filters — particularly OAuth2 resource server filters — was critical for correct authentication flow.