A cURL developer implements and utilizes the cURL command-line tool in their applications to transfer data using various network protocols. Their work involves making HTTP requests, testing APIs, handling user sessions, and managing cookies. They also create scripts to automate data transfer processes and debug network-related issues. They often work in conjunction with frontend and backend developers, integrating cURL commands into larger software systems. cURL developers are also responsible for ensuring the security and efficiency of data transfers, and may also be involved in optimizing the speed and performance of these transfers.