The consultancies and vendors that actually do RPG (IBM i / AS/400) modernization work, and what each one specializes in. This is a general market overview, not a paid placement or an endorsement.
The original platform vendor
IBM still owns the compilers and the hardware most COBOL, PL/I, RPG, and HLASM code runs on. Its own consulting arm pairs migration and refactoring services with tooling for code analysis and COBOL-to-Java transformation on IBM Z, alongside watsonx Code Assistant for Z, an AI-assisted code explanation and conversion tool launched in 2024.
Best for: Staying on the mainframe and modernizing around it, rather than off it.
Automated COBOL, RPG, Natural, and PowerBuilder to Java or C# conversion
Blu Age was founded in France in 2000 and acquired by Amazon Web Services in November 2021; its automated conversion platform now ships as part of AWS Mainframe Modernization. It converts COBOL, RPG, Natural, and PowerBuilder source into Java or C#, and is the vendor behind one of the largest publicly documented conversions in the industry: 12 million lines of COBOL converted to Java for an insurance client in roughly six months.
Best for: Organizations with an AWS-centric cloud strategy converting at scale, not maintaining in place.
Legacy language tooling and modernization products
Rocket builds developer tooling, DevOps pipelines, and modernization products specifically for mainframe languages, generally aimed at keeping and improving existing code rather than replacing it outright.
Best for: Teams that want to keep the codebase and modernize how it's built and deployed.
IBM i application lifecycle management and modernization
Founded in 1992 by Philippe Magne in Chavanod, France, ARCAD Software specializes in managing and modernizing IBM i application development environments, with version control and code quality analysis for RPG, COBOL, CL, and other IBM i languages, combining application modernization and DevOps tooling in one product line.
Best for: RPG and IBM i shops that want modern DevOps practices around code they are keeping.
API-led legacy integration
OpenLegacy generates APIs directly from existing mainframe programs and data, letting new applications call legacy systems without touching or rewriting the underlying code.
Best for: Exposing legacy business logic to new apps without a migration project at all.
Large-scale enterprise modernization consulting
A large systems integrator with a broad mainframe modernization practice, typically engaged for enterprise-wide transformation programs rather than a single application.
Best for: Large organizations running a formal, multi-year modernization program.
Offshore-heavy delivery at scale
Large Indian IT services firms with deep bench strength in COBOL, RPG, and PL/I maintenance and modernization work, typically engaged for ongoing managed services or staffing gaps.
Best for: Filling a workforce gap on an ongoing maintenance workload, not just a one-time project.