William Thoi developed a focused analytics feature for the stripe/stripe-js repository, introducing robust TypeScript type definitions to support embedded checkout analytics. He designed comprehensive interfaces for events such as checkout rendering, device data collection, promo code application, line item changes, and submission, ensuring stable data contracts for analytics tracking. By leveraging his expertise in API design and TypeScript, William’s work improved the reliability and structure of business intelligence data, enabling more accurate analysis of user behavior and checkout performance. This contribution laid a solid foundation for future analytics enhancements and facilitated better cross-team collaboration on data-driven product improvements.