During April 2026, this developer enhanced the woowacourse-teams/2025-bom-bom repository by delivering API DTO validation improvements focused on data integrity and error messaging. Working primarily with Java and backend development, they refactored annotation conventions in the MaeilMailSubmitAnswerRequest class and enforced non-blank and non-null constraints on response DTOs. This approach standardized validation behavior across the API layer, reducing the risk of invalid data submissions and improving maintainability. The work emphasized aligning validation practices with project standards, resulting in more reliable API responses. No critical bugs were addressed, as the month’s efforts centered on quality improvements and validation consistency.