Developed and delivered fee management features for DEFRA’s epr-payment-service and epr-payment-facade repositories, focusing on accurate 2026 registration fee handling and flexible compliance calculations. Leveraged C# and Entity Framework to implement EF Core migrations and DateTimeKind adjustments, ensuring precise fee application and robust database integrity. Introduced a conditional flag in the API to allow dynamic inclusion of registration fees in compliance scheme calculations, supporting configurable fee management for multi-year registrations. The work enhanced financial accuracy and compliance readiness, with careful attention to backend development, database migrations, and unit testing, reducing the risk of incorrect charges across integrated payment services.