Sebastian Wells contributed to the centrapay-docs repository by enhancing both data modeling and developer documentation over a two-month period. He introduced a promotionId field to the promotion membership model, clarifying the relationship between promotions and memberships to improve data integrity and support more accurate analytics. Sebastian also delivered comprehensive API documentation for a new Applet API, including a create-applet endpoint and updated navigation to streamline onboarding for developers. His work relied on JavaScript for model changes and Markdown for documentation, demonstrating a focus on clear, maintainable code and thorough documentation to support both business reporting and developer experience.