During a two-month period, Jeroen Meijer enhanced API reliability and documentation across several Java-based backend projects. In the grpc/grpc-java repository, he improved null-safety by annotating StatusException.getTrailers() with @Nullable, clarifying its contract and reducing the risk of NullPointerExceptions for downstream users. Within the spring-grpc and spring-framework repositories, Jeroen refactored in-process gRPC channel documentation and Javadoc for clarity, and introduced an OverflowStrategy getter in ConcurrentWebSocketSessionDecorator, accompanied by targeted unit tests. His work focused on API design, backend development, and code refactoring, resulting in more maintainable codebases and improved onboarding for developers through clearer documentation and robust property exposure.