Duc To Manh contributed to the mezonai/mmn repository by enhancing backend reliability and deployment workflows over a two-month period. He improved the test suite by refining TypeScript imports and strengthening unit tests, ensuring correctness in gRPC client interactions. Addressing a bug in entry hashing, he introduced defensive logic in Go to gracefully handle empty transaction lists, preventing potential runtime errors. In DevOps, Duc restructured Docker Compose configurations, reallocating JSON-RPC service ports to avoid conflicts with the indexer and synchronizing host mappings for seamless deployments. His work demonstrated depth in backend development, testing, and container orchestration, resulting in more stable operations.