Hieu refactored the mezonai/mmn-tx-explorer codebase to improve consistency and readability, focusing on backend development with Go and API design. He standardized variable names, enhanced error handling, and adjusted function signatures to create a more maintainable and approachable code structure. By resolving linting issues across multiple files, Hieu improved CI reliability and reduced technical debt, laying a stable foundation for future features. His work included expanding inline documentation, which accelerates onboarding and supports cross-team collaboration. The depth of the refactor addressed both immediate maintainability and long-term scalability, demonstrating a methodical approach to backend engineering and code quality.