Worked on backend reliability improvements for the misskey-dev/misskey repository, focusing on concurrency control within the announcement workflow. Addressed a race condition by ensuring the Announce object’s lock is consistently acquired in the announceNote function, including when requests originate from relay actors. This backend fix enhanced data integrity by enforcing reliable locking semantics across all announcement paths. The solution was implemented using TypeScript and leveraged Redis for backend state management. Over the course of the month, contributed a targeted bug fix that strengthened the robustness of announcement handling, demonstrating attention to detail in backend development and concurrency management practices.