Services / AS/400 management system
AS/400 management system: modernise it without throwing it away
If your business runs on an AS/400 (today IBM i) management system, the system is not the problem: it is reliable and the data is intact and orderly. The problem is that it lives isolated from the rest and depends on ever rarer skills. It can be modernised and connected to the outside world, step by step, without rewriting it and without stopping the business.
What an AS/400 management system is, in brief
AS/400 is neither just software nor just a database: it is an integrated platform where hardware (IBM Power servers), operating system (IBM i) and relational database (Db2 for i) are designed as one. On top run the management applications, often written in RPG, holding decades of business rules refined by real cases. It is a machine famous for reliability: rarely is it the reason people want to change.
The problem is not the machine: it is skills and isolation
IBM i is alive and supported, and it runs on new hardware without rewriting the code. The real reasons an AS/400 system causes anxiety are others: the people who maintain it, RPG programmers, are retiring and replacements are hard to find; the system does not talk to the website, e-commerce, e-invoicing, the warehouse; and nobody is quite sure whether it is still worth keeping. These are problems of skills and connections, not of the machine’s power.
Modernise or replace? How to decide
Redoing everything on a new ERP is the most expensive and most exposed project: months of work, the dreaded switchover blackout, and the risk of throwing away precious business rules. Replacing makes sense only if the processes are by now completely misaligned with the system. In most cases the opposite is worth it: keep the core that works and build around it the modern layer it lacks. And beware a common misconception: moving the data to another database does not free you from the dependency, because the real dependency is in the business logic, not the data, which on AS/400 is already relational.
What gets done, in practice
- An API layer over the programs and the Db2 database, to let the system talk to the web and to other systems.
- A modern web interface in place of the character terminal (green screen), where needed.
- Integration with e-commerce, e-invoicing, warehouse and customer/supplier portals.
- Gradual migration: old and new coexist, functions move over one at a time, without stopping the business.
The modern layer is built with widespread, sustainable technologies (Java back-end with Spring Boot, web front-end) that read from Db2 for i and, where business rules apply, call the existing programs through stable channels, without rewriting the logic inside. From the outside the system becomes a service like any other; inside, it stays as it is.
Securing an AS/400 exposed to the network
A system born to sit locked in a machine room, once connected to the internet, multiplies its attack surface. Modernisation is the chance to secure it: the API layer becomes the control point where it is decided who can do what, requests are validated and access is tracked, with least privilege and GDPR compliance. Security is part of the project, not a patch added at the end.
What is not included
In fairness: the work is the modern application layer and its security. It does not include RPG development or maintenance, nor managing the hardware or hosting of the IBM i server: those need dedicated people and providers. Knowing where one competence ends and another begins is part of doing the work well.
How it starts
The first step is a low-cost initial analysis: understanding how the system is built, which data and programs really matter, where the security risks are and which integration is worth starting from. From there, a phased quote with costs and timelines set before starting. The investment stays under control and the system never stops.
Frequently asked questions
What is an AS/400 management system?
It is the management software that runs on an AS/400 system (today IBM i): an IBM platform integrating hardware, operating system and relational database. The application is often written in RPG and holds decades of the company’s business rules.
How does modernising an AS/400 system work?
A modern layer is built next to the system: APIs over the programs and the database, a web interface and integrations. The system stays in production and functions migrate gradually, without rewriting it and without stopping the business.
Is it still worth keeping the AS/400, or should it be replaced?
In most cases it is worth keeping and modernising it: it is reliable, supported and holds precious business rules. Replacing it entirely makes sense only if the processes are by now completely misaligned with the system.
Does it integrate with e-commerce, invoicing and the warehouse?
Yes. Exposed via APIs, the AS/400 system exchanges data in real time with e-commerce, e-invoicing, warehouse and portals. Only what is needed is exposed, in a controlled way.
Is the work done remotely?
Yes, almost always. Access to the system, analysis of Db2 and building the API layer are done remotely, with dedicated credentials and securely, without stopping the systems.
How much does it cost to modernise an AS/400 system?
It depends on the integrations and interfaces actually needed. It starts with a low-cost initial analysis and a phased quote, with costs and timelines set before starting.
Deep dive: modernising a legacy AS/400 system without rewriting it