During September 2025, contributed to the GreenCityUser and GreenCity repositories by enhancing backend reliability and maintainability. Focused on reinforcing test coverage for the Telegram feedback workflow, unit tests were added to the email subsystem to align with SonarQube standards and ensure robust validation. Introduced validation annotations in UserTelegramFeedbackDto to enforce data integrity for Telegram feedback submissions, addressing fields such as chatId and rating. In the GreenCity repository, deprecated the Fondy payment method by removing unused keys from ClusterExternalSecret configuration, streamlining secret management. Work leveraged Java, Spring Boot, and YAML, emphasizing backend development, configuration management, and data validation best practices.