Worked on stabilizing the data import workflow in the microsoft/fhir-server repository, focusing on backend reliability and robust error handling. Addressed a critical bug by implementing dedicated handling for import data constraint violations, ensuring that invalid data triggers a clear BadRequest response with specific error codes and messages. This approach, developed using C# and SQL, improved the clarity of feedback provided to API consumers and reduced ambiguity during bulk data imports. By enhancing error messaging and enforcing constraint compliance, the work reduced support overhead and helped maintain data integrity, demonstrating a methodical approach to backend development and API reliability.