Andrey Bykov contributed to the topmonks/hlidac-shopu repository by enhancing backend reliability and integration quality over a one-month period. He implemented robust GraphQL error handling in Node.js, ensuring that failures now throw exceptions rather than logging silently, which prevents undetected data issues. Andrey also corrected country-specific URL generation for Pilulka Black Friday promotions, improving user navigation across regions. Additionally, he externalized the Apify package as a peer dependency using npm, reducing version conflicts for consuming projects. His work demonstrated a solid grasp of backend development, package management, and JavaScript, addressing both feature delivery and critical bug fixes with technical depth.