During June 2025, Seolhee Choi developed foundational business features for the seolhee-choi/B2B-Demo repository, focusing on Menu Management and Sales Management systems. She implemented backend scaffolding using Java, MyBatis, and Spring Boot, enabling user-specific menu retrieval and efficient hierarchical data structuring. For Sales Management, she delivered robust registration and retrieval flows with input validation to ensure data integrity. To streamline development, she temporarily bypassed Spring Security, accelerating iteration while maintaining plans for production security. Her work demonstrated depth in backend architecture, clear separation of concerns, and traceable commit practices, resulting in maintainable, testable code that supports rapid feedback and future enhancements.