Worked on the seolhee-choi/B2B-Demo repository to deliver foundational business features, including a Menu Management System and Sales Management functionality. Built end-to-end scaffolding for controllers, DTOs, mappers, and services using Java, MyBatis, and Spring Boot, enabling UI-facing menu retrieval by user and efficient hierarchical data structuring. Developed robust sales data registration and retrieval flows with input validation and data integrity controls. To accelerate development, temporarily bypassed Spring Security authentication and authorization, with plans to restore full security for production. Addressed one bug and maintained clear commit traceability, supporting rapid feedback cycles and iterative backend development throughout the project.