Marco Teodoro developed a Cancelable Delete Operation for the umbraco/Umbraco-CMS repository, focusing on enhancing API reliability and user experience. He refactored the deletion pipeline in C# to improve maintainability, extracting core logic into private methods and ensuring DRY principles across synchronous and asynchronous paths. By integrating notifications, he enabled cancellation of delete requests and extended error handling to prevent duplicate UI errors. Marco expanded end-to-end and integration test coverage using unit testing best practices, split service classes for cleaner code, and implemented clean-up patterns to support reliable CI. His work addressed maintainability and readiness for upcoming Umbraco 18 requirements.