A Mainframe Developer is responsible for designing, coding, testing, and debugging large-scale mainframe systems. They work with COBOL, JCL, , and other mainframe technologies to develop robust and secure applications. They also handle data processing and storage tasks, ensuring efficient and reliable system performance. The developer troubleshoots issues, optimizes system capabilities, and collaborates with other IT professionals to integrate mainframe systems with other software. They also maintain system documentation, enforce coding standards, and participate in the full development lifecycle. Their role is crucial in businesses that rely on mainframe computers for complex, high-volume data processing.