Worked on the amzn/selling-partner-api-models repository, delivering two core features over two months focused on enhancing seller data management and analytics capabilities. Developed and updated GraphQL and Java-based API schemas to support richer seller data, improved product listings, and more accurate stock tracking, while ensuring backward compatibility for existing integrations. Enhanced the Economics Analytics Data Kiosk schema to extend date ranges and introduce new input types, enabling more precise seller economics data simulations and deeper analytics. Prioritized clear developer documentation and traceable commits, demonstrating a methodical approach to backend development, API design, and data modeling within a complex, evolving platform.