Bring legacy code onto a platform your team actually wants to work in
You’re probably sitting on systems that still do the job, but that no one wants to touch anymore. It might be Java from the early 2000s, mainframe, Visual Basic, C, or C++. The code is still alive, but development has stalled. Rewriting it by hand has long been too expensive, too slow, and too risky to justify. So it has been left as is.
That is exactly what has changed.
We have built our own AI agents that read, interpret, and translate legacy code into a modern architecture that is stable, secure, scalable, and easy to extend. What used to require a double-digit number of developer-months can now be done in a fraction of the time, with greater consistency and full traceability. For the first time, there is a real business case for modernization that actually adds up.
The goal is not to create a copy of the old system, but an application your developers actually want to work in, one you can recruit for, and one that can handle both scale and decades of continued development. We often modernize onto a contemporary Microsoft stack, for example .NET at the core with React on the frontend, but we adapt to your reality and your preferences.
How our agents do the job
Our agents do not have a catchy product name. They are part of an internal framework we have built on Claude, and continue to refine in every engagement. We want the tool to serve the client, not the other way around.
The agents read and understand existing code, regardless of language or standard. They uncover business logic and dependencies that often are not documented anywhere. They propose and generate new code in the target architecture. They create tests and verify that the functionality holds together. Throughout the process, our consultants stay in the loop to review, adjust course, and make the decisions that require experience.
The real gain is not just speed. It is consistency. When the agents handle the heavy lifting, our developers can spend their time where it actually creates value: architecture, business logic, and quality.
This is what we solve
Modernization becomes relevant when the old system costs more in friction than it delivers in value. We often meet organizations that describe the situation roughly like this:
“Technical debt is slowing us down”
Every small change takes weeks, and every release requires weekend work. The pace of development no longer matches the needs of the business.
“We can’t make the business case for a rewrite add up”
Historically, the cost has simply been too high relative to the benefit. With AI-driven modernization, that equation changes fundamentally.
“The system is starting to become a security risk”
Frameworks without support, vulnerabilities that cannot be patched, and an ever smaller group of people who actually understand the code.
“We can’t find developers for the stack”
Very few new developers want to build their career on a platform from 2002. The skills shortage becomes a business risk in its own right.
Our process
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Understand the current state
We analyze your existing codebase, dependencies, and architecture, using both our agents and experienced human eyes. The result is a clear picture of the current state and a realistic risk profile.
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Create a migration plan
We package the modernization into manageable steps, with a clear sequence, dependencies, and boundaries. You get a plan that can be budgeted, defended, and followed up on.
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AI-driven rewrite
Our agents translate and refactor the code into the target architecture. Our consultants review, adjust, and ensure quality at every stage.
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Validate and refine
We verify that the new platform does everything the old one did, and more. Testing, performance, and security are built in from the start.
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Handover of a platform built for the future
You get a modern, stable, and extensible foundation to build on. Ready for continued development, integrations, and whatever capabilities come next.
Why Esatto?
We make modernization a business case you can actually justify
We do not just talk about technical debt. We show where the value is and build a case that can stand up in front of a CFO.
We use AI where it actually makes a difference
Our agents are not a marketing label. They are the tools we use every day to make modernization faster, more cost-effective, and safer.
We combine technical depth with business understanding
We are a partner that understands both how the code should be written and why you are doing this in the first place.
We build for the next ten years
The new platform is not just modern today. It is built to withstand the needs your business has not even discovered yet.
Want to know more?
Daniel Nilsson
Managing Partner Stockholm