During January 2025, Chaso Lee focused on backend reliability for the CAUCSE/CAUSW_backend repository, addressing a critical data validation issue in the user sign-up process. Working in Java, Chaso implemented logic to ensure the first four digits of a student ID matched the admission year, preventing invalid registrations at the API boundary. This approach leveraged exception handling to provide explicit error messages, improving user feedback and reducing ambiguous failures. By strengthening validation and error reporting, Chaso enhanced data integrity and streamlined downstream processing. The work demonstrated depth in API development and backend engineering, with a targeted fix that improved onboarding quality.