Worked on the SDA-SE/sda-dropwizard-commons repository to enhance interoperability and test reliability for backend services. Developed and delivered IssuerClient JSON Content-Type Header Support, enabling the issuer client to handle both application/x-www-form-urlencoded and application/json token requests. This involved updating request headers and expanding unit tests to verify correct negotiation and acceptance of JSON content types, thereby improving compatibility with modern JSON-based APIs. Focused on API integration and backend development using Java, the work reduced integration friction for downstream services and improved onboarding for new clients. Emphasis was placed on robust unit testing to minimize regressions and ensure reliable token request handling.