An IBM iSeries developer designs, codes, tests, and debugs software applications on the IBM iSeries platform, also known as AS/. They use programming languages like RPG, CL, and SQL. Their work involves creating technical specifications, developing data structures, and ensuring the smooth integration of new applications with existing systems. They also troubleshoot and resolve any issues that arise within the iSeries applications, ensuring optimal performance. Additionally, they maintain and update the software as necessary, and may also provide technical support and training to users. They play a critical role in maintaining the efficiency and reliability of a company's IBM iSeries systems.