AS400 RPG developers spend much of their day coding, testing, and maintaining software applications on IBM iSeries systems, often using tools like RDi and SEU. They regularly troubleshoot system issues, implement business logic, and interact with DB2 databases. Collaboration with business analysts, QA testers, and other IT team members is common to ensure projects meet user needs and organizational requirements. Additionally, the role may involve translating user requirements into technical specifications and supporting legacy systems as well as modernization efforts. This dynamic mix of responsibilities keeps the work varied and engaging, while offering valuable experience in enterprise IT environments.