Aldo Mateli contributed foundational backend features and targeted bug fixes across two open-source repositories. For aio-libs/aiohttp, he integrated the Wireup Dependency Injection library, enabling DI container usage throughout the codebase and updating documentation to support a more modular, testable architecture. In facebook/pyrefly, Aldo addressed a static analysis issue by refining import diagnostics to correctly handle imports referenced only in __all__, reducing false positives and improving CI feedback. His work involved Python, Rust, and documentation, demonstrating depth in backend development and testing. The contributions focused on maintainability, extensibility, and reliability, with careful attention to code quality and developer experience.