An Apple Server Mavericks developer is responsible for developing and managing applications on Apple's OS X Server, known as Mavericks. This involves understanding the operating system's architecture, designing software solutions to work efficiently within this environment, and troubleshooting any issues that arise. They also ensure the security of the server, manage user access, and handle data storage. They may further work on enhancing system performance, maintaining system updates, and integrating various services like email, contacts, and calendar. Their role is crucial in ensuring smooth, efficient, and secure operations on the OS X Server platform.