Liam Allan Shares What’s Coming Next With Code For IBM i

June 23, 2025 Alex Woodie

The rise of Code for IBM i arguably is the best IBM i technology story of the past few years. The VS Code development environment came out of nowhere to challenge Rational Developer for i as the pre-eminent developer tool on the platform. And according to Liam Allan, who started this whole thing, Code for i is only going to get better in the months and years to come.

There is clear and unmistakable momentum behind VS Code and Code for IBM i, the VS Code plug-in that Liam Allan created back in 2021 while working at Seiden Group. In November 2022, when Allan gave an update on the project at the COMMON NAViGATE conference, there were 10,000 installs of Code for i from the GitHub repo where the project is managed. The project had 147 stars and 25 contributors. Today, the project boasts 53,000 installs, 322 stars, and more than 50 contributors.

The project likely already exceeded IBM’s Rational Developer for i (RDi) as the number one integrated development environment (IDE) on the platform, if Fortra’s 2025 IBM i Marketplace study is any indication. The survey that took place in late 2024 indicated that 54 percent of survey takers used RDi compared to 53 percent for VS Code, basically a dead heat. That was a big change from the previous year, when 56 percent used RDi while only 37 percent used VS Code. About 80 percent of the installed base still uses green screen development tools, like SEU, however.

Allan, who joined IBM as a software developer in 2022, says the backing from Big Blue has been critical to Code for IBM i’s success.

“What’s great is IBM is investing in this product as well. It’s not just me anymore. It’s not just the open source community. It’s also IBM who is actually saying we see it, we value it, let’s continue to look after it,” Allan tells IT Jungle. “And that means a lot to me personally, but also the community should see that as a really good thing, I think.”

2025 IBM i Marketplace Study report

On a technical level, there are bugs that Allan and the Code for IBM i community “would have never been able to fix” if they were working without IBM’s help and blessing. “Let’s just start there,” Allan says. “There’s stuff that we have discovered that we would have never been able to have done had it not been for people that I’ve met internally at IBM. So I’m very grateful for that, obviously.”

That’s not to say that Code for i is rife with bugs. Quite the opposite, in fact. According to Allan, the open source software is remarkably stable and bug free. That doesn’t mean there aren’t bugs – every piece of software has bugs –but Allan seems quite happy at the current state of the project.

“Four years later, it’s pretty stable,” he says. “What more could you ask for? An open source project that is heavily used and is fairly stable. How incredible is that? Love that. Honestly, I sleep at night. I can go to bed at night and not worry about folks. It’s great.”

Even the compiler is now working well with Code for i, which was a major effort that involved some pretty big architectural changes by IBM. The official IBM i Debugger product used to be bundled as a JAR file with IBM Toolbox for Java, and is directly integrated with RDi, which is itself built on the open source Eclipse platform integrated development environment, which is written in Java.

“When it [the compiler] came out, it worked. But configuring it was tedious, tedious work. It wasn’t fun. There were issues. It sucked,” Allan says. “But now the setup happens in Navigator for i. The experience is significantly streamlined in comparison to what it was before. So we’re seeing less issues across the board. We’re finding the user experience has significantly improved and that has worked out excellently, so I’m really happy to see that.”

Another big focus for Allan and the IBMers that he works closely with on Code for i, including Sanjula Ganepola, Julia Yan, and Adam Shevivy (who are some of the new crop of younger devs at IBM that we wrote about last week), is the database extension. The database extension, which provides SQL functionality to VS Code, was announced in late 2023 and is currently in preview. It is also managed on GitHub.

“The database extension has continued to get bigger,” Allan says. “Scott [Forstie, the Db2 for i architect] isn’t pressuring me, but he definitely keeps me on the ball with things that we should be working on and improvements that we get from customers. He and I have worked very, very closely.”

Liam Allan is an advisory software engineer with IBM.

Allan and the other Code for IBM i developers embarked upon a “huge change” with the internals of the project earlier this year, Allan says. The effort was tremendous but it has put the team in a good position to move faster and do better work when it comes to developing additional Code for IBM i extensions.

“Developing extensions can be sometimes kind of tedious to test. We did a fairly large cleanup, and now we’re finding that we can have automated test cases, for example,” Allan says. “They run automatically when we make changes or someone makes a pull request. Things that make our development life easier to get things out the door faster. Those are big.”

That development pain will pay dividends for the IBM i community later this year when the Code for IBM i testing extension comes out. The testing extension will make it easier for developers to write test scripts to test their new RPG, COBOL, CL, or SQL code they develop within Code for IBM i.

“You don’t need to compile anything yourself. You just write the tests, click the button, and it will do all the work for you. It’s it really is fantastic,” he says.

It has taken some time to get here, but Allan is happy that the extension is nearing its first release to the coding public.

“That was work that I wanted to do years ago,” he says. “I kind of started out with Code Coverage a few years ago, and I’m really glad to see Sanjula has dedicated the time to make that work. So I’m really happy to see that coming very soon.”

Allan – who occasionally works on other projects for IBM, such as the new Mapepire database connector that IBM released last September or the Watson Code Assistant (WCA) for IBM i product that will soon be in public preview – had one more big Code for IBM i update for us: A display file editor.

The work has begun on creating a display file editor that will allow users to create and maintain 5250 screens within VS Code, much like Screen Design Aid (SDA) works now in the Application Development Toolset (ADTS), according to Allan.

Clearly, IBM wants people to develop modern applications with modern tooling, which VS Code and Code for IBM i definitely are. However, the reality is that not every IBM i shop is ready to completely change how they develop and what they develop at the same time, so IBM is giving them the opportunity take baby steps and develop green screen apps within VS Code.

“Truth be told, people do have to maintain green screens at the end of the day,” Allan says. “Entire large corporations are running green screen applications, and while some of them are in the process of migrating those to Web apps and building with React and things like that, we still encourage people to go do that.”

“At the end of the day, this might be the last straw,” he continues. “We might build a green screen designer that does the bare minimum for them to do their jobs, but not encourage them to make new ones.”

Last but not least, IBM is also working on developing a technical support program for Code for IBM i. Some IBM i shops aren’t satisfied with getting support from the open source community and demand a professional program to be in place before they adopt the tool. This new program was announced at the recent COMMON POWERUp conference in Anaheim, California, and will come out later this year.

Allan isn’t driving the support initiative, but he is involved because he leads the development of the product. Allan will also be available as a Level 3 support tech for the toughest problems in Code for i. But don’t hold your breath you will ever get Allan on the phone. “We never get Level 3 type bugs,” he says.

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