Worked on the CMSgov/beneficiary-fhir-data repository, focusing on Explanation of Benefits (EOB) Version 3 bug fixes and data validation enhancements. Addressed issues in coding systems and improved financial data validation logic, which increased data integrity and reduced discrepancies in beneficiary-fhir data workflows. Utilized Java and FSH to validate and correct coding system mappings, ensuring better interoperability with downstream systems. The targeted bug fix for BFD-4419 improved repository health by reducing the risk of related defects and preventing incorrect payment calculations. This work contributed to more accurate reporting and supported regulatory alignment, leveraging skills in API development and backend engineering.