During May 2025, Jihwan Kim focused on backend development for the redis/node-redis repository, addressing robustness and developer experience in cluster operations. He delivered a targeted bug fix in TypeScript and Node.js, modifying the cluster.sUnsubscribe API to accept an optional listener parameter. This change removed the requirement for a callback, streamlining the unsubscribe workflow and reducing boilerplate for developers working with Redis clusters. By making the API more ergonomic and non-breaking, Jihwan improved reliability and usability in multi-node deployments. His work demonstrated a thoughtful approach to API design, prioritizing maintainability and ease of use for the Redis client community.