Also known as: Report Program Generator, RPG IV, ILE RPG
A programming language, originally built for business reporting, that is still the dominant application language on IBM i systems today.
RPG (Report Program Generator) is a programming language originally created for business reporting in the 1960s, long before the AS/400 existed, and carried forward as the dominant application language on OS/400, then IBM i. Modern RPG IV (also called ILE RPG) is a fully current language actively maintained by IBM, capable of free-form syntax, calling web services, and integrating with SQL, not the fixed-column legacy format many people picture.
A huge share of AS400/IBM i migration conversations are really about protecting decades of working RPG business logic, not rewriting it. A well-planned hardware migration to current Power Systems keeps existing RPG applications running, which is the main reason IBM i shops migrate hardware on a cycle instead of replacing the application layer.