A Gearmand developer is responsible for creating and managing the Gearman system, an open-source application framework designed for distributing appropriate computer tasks to multiple machines, improving load distribution and redundancy. They design and implement distributed system solutions, ensuring efficient data processing and task execution. They also troubleshoot and optimize Gearman servers for better performance. Their work involves a lot of coding, system design, and sometimes, network administration. They play a crucial role in managing high-volume, data-intensive applications and ensuring the robust and reliable operation of distributed systems.