Worked on enhancing the nats.docs repository by delivering targeted documentation for NATS JetStream’s optimistic concurrency controls. Focused on clarifying the use and semantics of the Nats-Expected-Last-Subject-Sequence-Subject header, the work provided detailed guidance to help developers understand subject-level concurrency and apply safer usage patterns in distributed deployments. The documentation was authored in Markdown, leveraging technical writing and documentation skills to improve clarity and accessibility. This contribution aimed to streamline onboarding for new users and reduce support overhead by making complex concurrency concepts more approachable, reflecting a focused and in-depth approach to technical documentation within the NATS ecosystem.