Worked on the YSTEMandChess/react repository to enhance lesson management by introducing a default lessons file and removing duplicate lesson definitions, streamlining the workflow for greater reliability. Focused on backend development using Node.js, Express.js, and MongoDB, the work included refactoring middleware to address hygiene issues, missing imports, and restructuring for improved maintainability. Token validation logic was strengthened with enhanced error handling, resulting in a more secure authentication process. These updates reduced maintenance overhead and lowered production risk, preparing the system for future scaling. The changes collectively improved the robustness and security of lesson management within the application’s backend infrastructure.