Filip Cacky modernized the ARIMA core in the Nixtla/statsforecast repository, updating the C++ implementation to use newer standards and safer data types, which improved numerical stability and reduced edge-case risks in statistical modeling. He refactored the codebase for maintainability, introducing std::span for safer array handling and enhancing transformation reliability. In the netflix/metaflow project, Filip delivered asynchronous runner improvements by strengthening signal handling, error management, and inter-process communication through a temporary FIFO mechanism. His work leveraged C++, Python, and asynchronous programming, demonstrating depth in both numerical methods and systems reliability while laying a foundation for future extensibility and robustness.