Why migrate from RPG to Python?
The choice of migration target shapes everything that follows: who you can hire, what ecosystems you can integrate with, and how your team will develop the system for the next decade. Here is the case for Python.
The language your team already wants to use
Python is the most widely learned programming language in the world. It is the first language taught in most universities. It is the primary language for data science, machine learning, automation, and modern web APIs. When you post a Python job, you reach a vast pool of candidates — including people with deep analytical and data capabilities that RPG and Java developers rarely have.
For organisations whose RPG systems process financial data, operational data, or any kind of business intelligence, a migration to Python is not just a modernisation of the code — it is an unlocking of capability. Your business logic, once in Python, can be connected to pandas, NumPy, scikit-learn, and the entire PyData ecosystem without an additional translation layer.
The question is not whether Python is popular. It is whether Python is right for your specific situation. We discuss this honestly — including cases where Java is the better choice.
"Python doesn't just replace RPG — it opens doors that RPG never could."
Python migration typically means moving off IBM i — and that is often exactly what you want
Python can run on IBM i through PASE — the Unix-like compatibility environment — but this is not the same as Java running natively on the JVM. PASE adds overhead and complexity, and most organisations migrating to Python are doing so precisely because they want to leave IBM i behind. A Python migration therefore typically involves moving to Linux or a cloud environment.
For many organisations, this is not a constraint — it is the goal. The IBM i hardware and licensing costs are a significant burden, and moving off it is part of the business case for migration. The combination of code migration (RPG → Python) and platform migration (IBM i → Linux or cloud) is something we plan carefully. The platform move does not need to happen on day one — the Pilot and early iterations can run alongside IBM i while the target infrastructure is prepared.
For organisations that want to stay on IBM i and run cleanly without PASE overhead, Java is the stronger target — it runs natively on the JVM, which IBM i has supported since V4R2. If that is your situation, we will tell you honestly and point you to rpg2java.com.
Comparing migration targets
| Criterion | Python | Java | C# | TypeScript |
|---|---|---|---|---|
| Data science / ML ecosystem | Best in class | Limited | Good | Growing |
| Developer talent pool | Very large | Very large | Medium | Large |
| Runs on IBM i (via PASE) | Yes — via PASE | ✓ | ✗ | ✗ |
| Enterprise ecosystem | Excellent | Excellent | Excellent | Growing |
| Cloud & DevOps integration | Excellent | Good | Good | Good |
| Readable / learnable syntax | Excellent | Good | Good | Good |
| Type safety (optional) | Type hints + mypy | Strong | Strong | Strong |
Note: We also offer RPG-to-Java migration at rpg2java.com — a service by Strumenta. If Java is the better fit for your situation — particularly if you want to stay on IBM i without PASE overhead — we will tell you honestly.
A language your organisation will be building on for the next 20 years
Python is consistently ranked as the most popular and most wanted programming language in developer surveys. It is the language of data science, AI, and automation — and these are only growing in importance for organisations that rely on business data.
Python 3 has been the standard for over a decade, and the language is governed by a stable process (PEPs, the Python Software Foundation) that balances evolution with backward compatibility. The ecosystem is mature: pip, virtualenv, poetry, pyproject.toml — the tooling is standard and well understood.
For organisations migrating away from a decades-old system, the long-term trajectory of the new platform matters. Python's trajectory — toward AI, data, and cloud-native development — is the trajectory of modern software.
Not sure if Python is the right target for your codebase?
The Migration Pilot will give you a concrete answer on your own code. We'll also tell you honestly if Java would serve you better.
Start with a Migration PilotEUR 3,000 fixed price. 15-day money-back guarantee. We respond within 2 business days.