Over two months, Parfenov worked on the profcomff/dwh-pipelines and profcomff/rating-api repositories, building and refining data pipelines and backend features. He developed and enhanced Airflow DAGs for dynamic user permission management and improved timetable data ingestion, focusing on data integrity and maintainability. Using Python, SQL, and SQLAlchemy, he introduced schema migrations and optimized ETL flows, enabling more accurate and reusable data models. Parfenov stabilized production environments through targeted bug fixes, improved deployment reliability, and enabled cross-module data reuse. His work demonstrated depth in data engineering, database management, and pipeline automation, resulting in robust, maintainable, and reliable data workflows.