VS Code Will Be The Heart Of The Modern IBM i Platform

June 23, 2025 Sebastien Julliand

For application programmers, the workspace is not a place to sit with a screen, a keyboard, a chair, but rather is an integrated development environment within which code can be created, shared, compiled, and managed either inside the tool itself or through plug-in extensions that link it to other tools. IDEs have been around for decades and are not anything new. What is new is how suddenly popular one particular IDE – VS Code – has become.

For the past several years, nearly three quarters of the programmers in the world polled for the Stack Overflow Developer Survey say that they use VS Code, the tool let loose as open source by Microsoft a decade ago as a glorified code editor that has gradually evolved into a true IDE and spread like wildfire across the Windows, Linux MacOS platforms. VS Code can be used to create programs written in C, C#, C++, Fortran, Go, Java, JavaScript, Node.js, Python, Rust, and Julia on those platforms and, more recently, has been extended to work with the IBM i platform and its RPG, Java, and SQL applications.

It is not a question of if, but when, VS Code will eclipse – pun intended – IBM’s own Rational Developer for i IDE among the IBM i base. RDi is itself written in Java and is based on the Eclipse IDE that Big Blue open sourced in 2001 and was the most popular IDE for Java programming for about a decade, and over time Eclipse extended support to all of the popular programming languages.

VS Code started as an outsider, but now it is becoming the reference IDE for developing on IBM i. VS Code is not just a trend when we see that IBM is developing an AI-driven code assistant for the IBM i platform and it is going to integrate with VS Code and not with RDi. That sends a clear message to the community.

The community is also sending clear messages to IBM. We see more and more people giving sessions on VS Code at PowerUP 2025 and the COMMON Europe Congress 2025 conferences, and attendance was very high at these sessions. Everybody is talking about VS Code, the community is very lively, and nothing is happening with the other editors and IDEs. People can contribute to VS Code, either with ideas on how to make it better or by creating extensions or features for it, and perhaps most importantly, people can just download it and start using it. It’s fast and reliable, and unlike other IDEs, if you want to give it a spin, it is free and easy to do that.

There is a big difference between Eclipse and VS Code, and it is one that bears pointing out and it helps explain some of the momentum that we are seeing for VS Code in the IBM i community. ARCAD has built both RDI and VS Code plugins, and I can tell you that I love writing VS Code extensions compared to Eclipse plugins because one is easy and the other one is a big pain.

RDi is completely based on Eclipse, and it is really just a rebranded Eclipse with a few plug-ins provided by IBM. And even though Eclipse is open source at the core, the plug-ins provided by IBM for RDi are not, so you cannot get access to their code, which makes RDi partially closed. And on top of that, IBM has added a license checking that requires you to actually buy a license if you want to use those RDi plug-ins. This means the only place you can go to resolve a problem related to RDi is IBM. And IBM controls the pace of change for RDi and arguably has more limited resources than the vast VS Code user base. The VS Code is getting a lot of requirements from users, often being requested through GitHub, where VS Code is downloaded and bug fixes are pushed out. This is an easier mechanism than trying to work back through IBM or anyone else for that matter.

The thing to remember about VS Code is that not every feature from RDi will be included in VS Code. Sometimes, you will have to learn a new way of doing things, and IBM, once again, has been perfectly clear about this.

But the most exciting thing about VS Code is how it can revitalize the IBM i base. VS Code plus free format RPG plus SQL is an easy to use, modern platform, and programmers are familiar enough with Java and other languages that RPG will not be completely alien to them. This was not the case with fixed format RPG from days of old. So somewhere north of two things out of three to create modern applications is available – and popular – on the IBM i platform, making it look like other platforms. No need for SEU or PDM for 5250 greenscreens or the very slow RDi for more modern applications. New programmers know VS Code, and by supporting VS Code, IBM i now looks normal for the world’s programmers in a way that it did not until fairly recently.

And in fact, it is easier to get programmers using SEU and PDM to move to VS Code than it was to try to get them to move to RDi.

This is real progress, and brings hope for the IBM i platform. We get to look fresh and cool and modern and still retain all of the unique aspects of our platform.

From VS Code/Elias: Peek of an RPGLE procedure inside a CL being edited

I often get asked as to what ARCAD is doing in relation to VS Code. The answer is, a lot actually. It’s a key focus in our R&D. The ARCAD extensions bring important IBM i DevOps features directly into VS Code, which are now readily available in the marketplace. Let’s go through them.

Elias / Builder

With Elias, developers can work within “project mode”, a true Git-based IBM i development model, making it easy for both newcomers and traditional IBM i developers to get started:

Edit, compile, build your changes on any branch locally or remotely without manual check‑in/out–ARCAD handles it transparently. This conflict-safe branching makes concurrent development easy.
Browse repositories and check out components/version as you would in traditional 5250 or RDi
Explore cross-references (dependencies) in-editor via CodeLens (file declarations, procedure usage/imports/etc.) assisted by ARCAD’s metadata repository
Convert fixed-format RPGLE to free-format RPG on the fly
Automatically build (recompile) dependencies using ARCAD metadata. No need to maintain Makefiles – real-time cross-reference management creates personal builds and handles branch integration
Automate a CI/CD pipeline on IBM i. As soon as code is pushed, ARCAD creates a branch-specific library on IBM i, and triggers pipelines: compile, quality/security checks, vulnerability scans, unit/regression tests, reporting – all automatically
integrate seamlessly with existing DevOps toolchains (Git, Jenkins, SonarQube, Azure DevOps, etc.)

CodeChecker

ARCAD CodeChecker gives developers an embedded static analysis engine. Right from VS Code, they can scan RPG/COBOL for quality or security issues with rule sets and in-editor highlights tied to the Problems view.

iUnit

ARCAD iUnit creates and executes unit tests within VS Code – to automate developer-side testing, monitor coverage/performance, export to JUnit, and integrate into CI/CD flows.

Transformer Microservices

ARCAD Transformer Microservices detects similar chunks of code across an IBM i application, generates modular procedures, and replaces the duplicate code with a procedure call.

Taken together, these VS Code extensions for IBM i transform the editor into a robust IBM i DevOps IDE—bringing modern build automation, code analysis, test, and deployment tools into the familiar VS Code environment. It’s a powerful leap for teams modernizing RPG/COBOL workflows.

When transitioning to VS Code, Elias delivers a smooth learning curve: IBM i developers familiar with RDi or 5250 workflows can modernize without disrupting their habits, while newcomers benefit from a familiar, modern IDE that lets them easily switch between IBM i development and other technologies – all within a single, unified environment.

To find out more: Webinar: Embrace VS Code for IBM i Development

Sébastien Julliand is a product manager at ARCAD Software and has been working on bringing the IBM i and open systems worlds together for more than ten years. Driven by his enthusiasm for technical challenges and a strong development expertise in many languages, from RPGLE to Java, Julliand joined ARCAD’s research and development as a functional and technical advisor, becoming a specialist on a wide range of products. Julliand is also involved in the development of several ARCAD products, particularly those focused on DevOps, and is specifically the product manager for ARCAD CodeChecker, a source code quality checker for IBM i for which Julliand brings his experience as a day-to-day developer.

This content is sponsored by ARCAD Software.

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