Worked on enhancing the reliability of PostgreSQL Pub/Sub workflows in the rivet-gg/rivet repository by addressing a critical bug affecting subscriber cleanup. Focused on backend development using Rust, the work introduced per-subscriber cancellation tokens and dedicated cleanup tasks, ensuring that resource release and subject removal occur only when no subscribers remain. This approach eliminated shared cleanup state, preventing cross-subscriber interference and reducing the risk of unintended retries or duplicate executions. Leveraging asynchronous programming and database management skills, the changes improved the stability and correctness of production pub/sub systems without introducing new user-facing features during the development period.