Contributed to the IT-Academy-BCN/ita-challenges-backend repository by focusing on backend architecture modularity, test coverage, and code hygiene. Developed a new controller to host redistributed functions, accompanied by comprehensive unit tests using JUnit and Mockito. Addressed legacy code issues by cleaning up ghost changes across multiple service and test classes, and expanded test coverage for bookmarks and favorites features. Introduced documentation and repository scaffolding for bookmarks, normalized error messaging, and implemented targeted bug fixes to improve maintainability. Leveraged Java, Spring Framework, and MongoDB to deliver five new features and resolve seven bugs, enhancing reliability and clarity in the codebase.