What Do IBM i Shops Use To Write Applications These Days?
February 3, 2025 Alex Woodie
When it comes to languages and tools for developing applications on IBM i, there are a ton of options available for customers. Thanks to the PASE runtime, a variety of open source languages and runtimes have been brought to the platform, not to mention the time-tested ILE technologies from IBM. But what do IBM i shops actually use to write new apps? For answers, we look to Fortra’s 2025 IBM i Marketplace Survey results.
Fortra recently released the results for the 11th installment of its IBM i Marketplace Survey, which is based on surveys it conducted in late 2025 with 250 IBM i professionals from around the world. It’s not a perfectly randomized survey, which would be practically impossible to do, but it’s quite informative nonetheless about the IBM i installed base.
The section of the survey about the use of application development tools and open source tools, in particular, tells us quite a bit about the technological investments that IBM i shops are making in their systems and their software.
Languages used for new IBM i development 2025. (Source: Fortra IBM i Marketplace Survey Results 2025)
RPG is the number one programming language in 2025 and is used by 91 percent of the IBM i shops, according to Fortra’s survey. That’s not a surprise, as RPG has been the top language since Fortra (then Help/Systems) rolled out the first IBM i Marketplace Survey back in 2015. Following RPG were the other three languages – SQL, CL, and Java – that have anchored the top of this list since it was created.
Below the top four, there was not a ton of action among the lower tier of languages. PHP is used by 19 percent of respondent IBM i shops, about where it’s been for the past five years, while COBOL logged a 16 percent rating, the same as 2024 but down from the high of 20 percent in 2023 (the “COBOL renaissance” on IBM i may have finally plateaued).
One bright spot is Python, the uber-popular general-purpose language that is widely used not only for application development but for data engineering, analytics, and AI, too. Python was picked by 26 percent of Fortra’s survey respondents, a six percentage point increase from last year and a nine percentage point increase since 2021. In 2025, Python officially passed PHP as the most popular open source language on IBM i.
Close behind Python is Node.js, which logged a 21 percent rating in the Fortra survey. That’s up three percentage points in the past year, and eight percentage points since 2021, according to data from past Marketplace reports.
Languages used for IBM i development over time. (Source for data: Fortra IBM i Marketplace Results 2020 – 2025)
Rounding out the bottom are .NET/C#, which saw a four percentage point increase this year to 13 percent, and C++, which was down slightly at 8 percent, about where it’s been for the past decade. Ruby and Perl were up slightly to 2 percent, indicating there’s a steady but (very) small contingent of IBM i developers who continue to use these scripting languages.
IBM i chief technology officer Steve Will said it was “heartening” to see so many IBM i shops using good old Report Program Generator.
“We’ve tried to make RPG easier for brand new programmers who’ve never seen RPG . . . to pick it up and do new things,” Will said during a Fortra webinar discussing the IBM i Marketplace Survey results. “But it’s also the case that those open source languages that are a little further down, starting with Java, Python, node, etc., and they are being used as well because so many of the programmers who get hired by clients may not know RPG at the beginning, but they know one of those other languages and they can right away do stuff on IBM i.”
Open Source
All of the new development languages and runtimes on IBM i are open source. But in addition to languages and runtimes, there’s a variety of other open source being used to build, serve, and monitor IBM i apps, which Fortra tracks in a different part of its Marketplace Survey.
Open source technologies used on IBM i in 2025. (Source: Fortra IBM i Marketplace Survey Results 2025)
At the top of the 2025 list is the perennial open source favorite, the Apache HTTP Server, which has been IBM’s default choice for Web serving since it killed its proprietary HTTP Server for IBM i back in April 2018. Three out of five survey respondents indicate their shop uses the HTTP Server (the one powered by Apache), which is down from a high of 65 percent in 2021. Apache Tomcat, a Web application server, is used by about 26 percent of the IBM i installed base, per the results. That’s down slightly from last year’s survey.
A more interesting development arguably is the use of Git. Fortra recorded 29 percent of survey-takers saying their shop uses the open source change management software, a sizable eight percentage point increase from last year. Compared to 2020, when 16 percent of Fortra’s survey respondents said they used of Git, adoption of the open source software has nearly doubled.
“Really glad to see that the number of people using git is now almost up to 30 percent,” said Will, who also holds the titles of chief architect for IBM i and IBM Distinguished Engineer. “That suggests to me that a lot of people are doing DevOps kind of programming with IBM i, which is what we’ve been trying to push people towards. So it’s not a total win yet, but it’s getting there.”
Use of open source databases, such as MySQL, MariaDB, and PostgreSQL, ticked up one percentage point to 14 percent. That’s down from 18 percent in 2021, indicating only marginal interest in open source databases on IBM i. Use of Ansible, an open source IT automation tool, recorded its third straight year with 10 percent adoption. Jenkins, which is used to automate CI/CD application pipelines, ticked up to 8 percent after three straight years at 7 percent.
Open source technologies used on IBM i over time. (Source for data: Fortra IBM i Marketplace Results 2020 – 2025)
“We’ve made sure that some of the most important middleware that’s in the open source community can run on IBM i so that when you bring a new application in or a new application programmer, they can have the kind of tools they would expect to have on any platform so they don’t have to modify the way they want to do applications just because we have some sort of black box. So that’s why it’s there, and I’m glad to see it getting used.”
Near the bottom of the list are:
- Service Commander, a command-line admin tool, which rose two percentage points from last year to 7 percent;
- Node-RED, a Node.js-based scripting tool for IoT applications, which rose three points to 6 percent;
- Apache Kafka, the pub-sub framework for streaming data, which ticked up one point to 5 percent;
- And Apache Camel, the data integration middleware, which lost a point and ended up at 1 percent.
You can download your very own copy of the 2025 IBM i Marketplace Study and watch Fortra’s webinar from this link.
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The survey didn’t ask the important follow-up question:
How many IBM i shops are writing new applications in RPG?
You make a valid point, Roger.
RPG *is* IBMi, so IBM treat it well. I don’t think someone would pick a IBMi anew to develop java (a language btw that doesn’t make any sense to develop ERP stuff efficiently). You have already the i , and having so much flexibility under the hood to run many things is welcomed.
Can be pretty powerful (in my case it does some automatic basket analysis).
I run even some R based batch on the IBMi. Yep, guilty.