What modern IDE can we use with the IBM i System?

For modern development on the IBM i System, you have multiple IDE options. Some excellent, some expensive, some free, some regularly maintained and some stagnant.

At time of typing - December 2025 - my top 3 contenders are: IBM PROJECT BOB, MICROSOFT VSCODE, and reluctantly (just because of the price tag) IBM RDi

Visual Studio Code (VS Code)

VSCode is my Preferred IDE for a couple of main reasons:

  • VSCode is free (this is NOT the main reason but certainly something to consider)
  • VSCode is extensible with lots of opensource plugins developed by other IBM i Developers
  • VSCode is simply put, a very friendly and super powerful editor with a relatively short learning curve

This is a highly customizable and popular open-source IDE. With extensions like "Code for IBM i," you can connect to IBM i systems, edit, compile, and debug code directly from VS Code. It supports various programming languages used on IBM i, such as RPG, COBOL, and CL. 

IBM Rational Developer for i (RDi)

IBM Power System running IBM i Operating System AS400 iSERIES - Rational Developer for i RDi

A close runner up with arguably more IBM focused development experience. 

Built on the Eclipse platform, RDi is specifically designed for IBM i development. It offers advanced features like syntax highlighting, code completion, integrated debugging, and build automation.

RDi feels like it locks you into an IBM developing paradigm, and while it's got a few more features compared to VSCODE, it also feels clunky and bloated.

As a freelance developer, the huge annual license fee means I just cannot recommend it.

IBM i Modernization AI IDE - IBM Project BOB

IBM Project Bob - using for the first time in Windows Dark mode

BOB is the new Kid on the Block and has some super interesting features.

IBM Project BOB represents one of the most forward‑looking shifts in the IBM i development ecosystem. Designed to bring modern tooling, browser‑based workflows, and DevOps‑friendly practices to the platform, BOB gives developers a clean, containerized environment that feels contemporary without abandoning the strengths of traditional IBM i development. Instead of relying on heavyweight desktop installs or aging green‑screen editors, BOB delivers a streamlined, consistent workspace accessible from anywhere, ideal for teams embracing modernization, remote work, or cloud‑aligned development pipelines.

IBM Project BOB – Key Features

  • Modern Open‑Source Tooling Built on familiar technologies like VS Code components, Git, and open‑source extensions that streamline RPG, COBOL, and CL development.
  • DevOps Integration: It integrates with modern DevOps tools like Jenkins and Git, streamlining the development process.
  • Cloud‑Aligned Flexibility Designed for remote teams, hybrid environments, and organizations moving toward cloud‑friendly IBM i modernization.
  • Code Modernization: It includes tools for converting fixed-format RPG code to free-form RPG, making it easier for new developers to understand and work with.

Which do you choose?

Each of these IDEs provide robust tools and features to enhance productivity and streamline the development process on IBM i systems.

Personally, I recommend VSCODE, but try each and see where you feel at home 🙂

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