IBM Rational Developer for i
IBM's Eclipse-based desktop development environment for IBM i, where a programmer edits, compiles and debugs RPG, COBOL, CL, C and SQL against a connected system instead of working in a green screen. Version 9.9 became generally available on January 27, 2026. It matters to AI work mostly for what it does not have: IBM's RPG AI assistants ship as Visual Studio Code software, not as Eclipse plug-ins.
What RDi does
RDi is a program you install on your own desktop. It connects to an IBM i server and lets you work on the code that lives there. IBM's product page calls it "an integrated development environment (IDE) built on the Eclipse platform, designed for creating and maintaining applications on IBM i". An integrated development environment is one program that bundles the editor, the compile button and the debugger together.
For most of IBM i history the editor was SEU, the Source Entry Utility, a green-screen tool that shows a fixed block of lines and checks a line only after you leave it. RDi is to SEU what a word processor is to a typewriter. The mistake gets underlined while you type instead of after you print the page.
- Remote System Explorer, the tree view that connects to the IBM i server so you can browse libraries, objects and source members.
- An editor for RPG, COBOL, CL and C that checks your syntax as you type. CL is Control Language, the command language of IBM i.
- Search, build, refactoring and program analysis tools, plus graphical debuggers.
- Host-connected and disconnected modes, so you can keep editing when the server is not reachable.
- Integration with IBM Rational Team Concert for lifecycle and change management.
Which version is current?
The RDi 9 line, from IBM's own lifecycle table
- June 14, 2013Version 9.0.0 reaches general availability, opening the RDi 9 line.
- April 28, 2023Version 9.8.0 reaches general availability, after an April 11, 2023 announcement.
- October 7, 2025IBM announces version 9.9.0. That is the same day IBM withdrew IBM i Merlin from marketing and service.
- January 27, 2026Version 9.9.0 is generally available. It moves to Eclipse 4.31 and adds better IFS project and Git support. The IFS is the Integrated File System, the part of IBM i that holds ordinary folders and files.
- April 30, 2026Version 9.8.0 reaches end of service. Version 9.6.0 had reached end of service a year earlier, on April 30, 2025.
- October 23, 2026Fix pack 9.9.0.8 ships, carrying security updates. Earlier 9.9 fix packs added multi-factor authentication support.
Dates from IBM's "Rational Developer for i Product Evolution" lifecycle table and the "Fix list for Rational Developer for i" page, both read October 28, 2026. One caveat worth knowing: IBM's separate lifecycle page for 9.9.0 lists general availability as December 5, 2025 under announcement letter AD25-0193, while the Product Evolution table and IBM's own community announcement both say January 27, 2026. We use January 27, 2026, the day IBM posted that 9.9 "is now generally available".
Are more IBM i developers using RDi or Visual Studio Code?
Visual Studio Code passed RDi in 2026, and that is the most important fact about RDi for anyone planning AI work. Visual Studio Code, usually shortened to VS Code, is Microsoft's free editor. It is where the IBM i AI tools live.
Share of IBM i developers using each desktop editor, Fortra IBM i Marketplace Survey
Numbers reported by IT Jungle on February 23, 2026 in "After A Few Short Years, VS Code Passes Rational Developer for i", by Alex Woodie, drawn from Fortra's IBM i Marketplace Survey. The middle year is where the gap closed: in the 2025 survey "54 percent said they used RDi compared to 53 percent for VS Code". A person can name more than one editor, so the figures add up past 100 percent.
The green screen is still the most used tool of all. The same surveys put ADTS at 80 percent in 2024, 77 percent in 2025 and 74 percent in 2026. ADTS is the Application Development ToolSet, the character-based tools shipped inside Rational Development Studio for i, product 5770-WDS, including SEU and PDM, the Programming Development Manager. RDi losing its lead to VS Code is not the same thing as shops leaving the green screen.
Can RDi use IBM's AI tools for RPG?
No. Nothing we read names RDi as a supported home for IBM's RPG AI assistants. The AI went to VS Code and stayed there. If your team works in RDi, adopting IBM Bob means adding a second editor, not installing a plug-in.
Where the IBM i AI tooling actually runs
| Tool | Editor it needs | What that means for an RDi shop |
|---|---|---|
| IBM Bob Premium Package for i | Visual Studio Code. IBM publishes it as the extension IBM/vscode-ibmi-bob, version 2.0.0 dated October 1, 2026, and its own manifest asks for a VS Code engine of 1.104.0 or newer | RDi cannot load it. A VS Code extension is not an Eclipse plug-in |
| Code for IBM i | Visual Studio Code. It is the extension that owns the connection the AI tools build on | There is no RDi equivalent. This is the layer IBM i AI help runs on |
| watsonx Code Assistant for i | Visual Studio Code in its preview, and now historical | IT Jungle reported on June 2, 2025 that "support for Rational Developer for i (RDi) is not currently in the plans" |
| RDi 9.9 itself | Eclipse 4.31, which RDi supplies | Neither IBM's RDi product page nor IBM's 9.9 general availability announcement mentions AI, watsonx or a code assistant |
Extension name, version and VS Code engine requirement read from the Open VSX registry record for IBM/vscode-ibmi-bob on October 28, 2026. The watsonx Code Assistant for i quote is from Alex Woodie's IT Jungle article "RPG Code Generation And The Agentic Future Of IBM i", June 2, 2025. That preview track was later superseded by IBM Bob.
A missing statement is not a promise. IBM has not said RDi will never get an AI assistant, and IBM has not said it will. What we can report is that as of October 28, 2026 no IBM source we read offers one for RDi. Ask IBM before you plan a budget around either answer.
How is it licensed?
RDi is paid software, unlike Code for IBM i, which is free and open source. IBM's product page offers a 120-day free trial and lists three editions and several license types. IBM does not publish a price on that page, so a real number comes from IBM or a business partner.
- Editions: RPG and COBOL Tools; RPG and COBOL plus Modernization Tools, Java Edition; and RPG and COBOL plus Modernization Tools, EGL Edition.
- License types: Authorized User perpetual, Floating User Single Install perpetual, and Floating Single Install Fixed Term.
- A floating license is shared from a pool, so it suits a team where not everyone writes code every day.
- Free trial: 120 days.
Related Terms
IBM i
IBM's operating system for Power servers running traditional AS/400-lineage business applications, with Db2 for i built directly into the OS.
AS/400
IBM's original 1988 midrange business computer platform; the term is still used informally to refer to IBM i systems and shops even though IBM has rebranded the hardware and OS multiple times since.
RPG
Report Program Generator, the primary business application programming language on IBM i and its AS/400 predecessors, still running the majority of production logic in most IBM i shops.
Free-Format RPG
A modern RPG coding style that drops the rigid column-based syntax of traditional fixed-format RPG in favor of freer, more readable statement syntax.
COBOL
A long-established business programming language still running production logic on IBM i and other legacy enterprise platforms alongside RPG.
Code for IBM i
Code for IBM i is the free, open source Visual Studio Code extension that lets a developer browse libraries and edit and compile RPG, CL, COBOL and C source on an IBM i over SSH. It owns the connection to the system, so other extensions plug into it rather than building their own, and IBM Bob Premium Package for i installs it automatically, which makes it the layer AI coding help on IBM i actually runs on.
IBM Bob (Project Bob)
IBM's generally available AI coding agent for IBM i, built as a fork of Visual Studio Code and tuned for RPG, CL, DDS, and SQL. Reached GA on March 24, 2026; Bob 2.0 and the IBM i-specific Bob Premium Package for i shipped June 24, 2026.
Bob Premium Package for i
The IBM i-specific add-on to IBM Bob, generally available June 24, 2026. It gives Bob about 40 skills and workflows and about 30 tools that work directly against QSYS, the IFS, CL, SQL and Db2 for i on a live system.
watsonx Code Assistant for i
IBM's November 2025 preview announcement of an AI code assistant purpose-built for RPG on IBM i. The preview track was superseded by IBM Bob, which reached general availability in March 2026.
IBM i Merlin
IBM i Merlin was IBM's browser-based development and modernization workbench for IBM i, built from IBM, Red Hat and ARCAD Software tools running in Red Hat OpenShift containers. It converted fixed-format RPG to free format, analyzed application impact and ran Git and Jenkins pipelines, and IBM withdrew it from marketing and service on October 7, 2025.