Learn RPG4 with Real Code Examples

Updated Nov 27, 2025

Introduction & Fundamentals Setup & Configuration Architecture & Deep Internals Performance & Security Development Workflow Learning & Career Growth Business & Strategy Examples

Architecture

ILE-based modular architecture

Service programs (shared libraries)

Activation groups

Db2 for i tightly integrated layer

RPG runtime within IBM i OS

Rendering Model

RPGLE program -> ILE binder -> Activation group -> Database + APIs -> Output or job completion

Architectural Patterns

Service programs for shared logic

File-driven business processing

SQL-centric modular code

Batch job orchestration

API-first architectures using RPG backends

Real World Architectures

ERP systems (Infor, JDE customizations)

Banking core logic

Supply chain batch workflows

Manufacturing resource planning

High-volume order processing

Design Principles

Consistency in enterprise data

High-volume transactional performance

Backward compatibility

Modular architecture

Strong IBM i integration

Scalability Guide

Split code into modules

Use SQL indexing

Optimize file access

Use commitment control

Distribute batch workloads via job scheduling

Migration Guide

Convert fixed-format to free-form

Refactor into service programs

Replace native I/O with SQL

Expose functionality via REST APIs

Modularize monolithic RPG programs