Worked on the ktorio/ktor-build-plugins repository to deliver OpenAPI contextual serialization enhancements, focusing on improved support for date-time and UUID types. Developed a new LocalDateTime endpoint and addressed processing issues for contextual serialization types, ensuring accurate API contract generation and better client interoperability. Utilized Kotlin for backend development and serialization, implementing comprehensive end-to-end tests to validate integration and edge cases. The work strengthened test coverage and reduced integration friction for downstream services by refining how serialization is handled within the API. This contribution demonstrated depth in API development, serialization strategies, and robust testing practices within a Kotlin backend environment.