The application you need has felt too risky to start.
So it waits while the market moves on. We build and deliver it for you, on a verified understanding of your system, with less time, money and team at risk.
The application you need, built and delivered.
Working, tested software in your repos, in the stack your team hires for, delivered module by module with progress you can see every week.
The new application
- Working software in the stack you choose
- Services and APIs where you need them
- Delivered module by module
Proof it works
- Parity tests against the old behaviour
- Test suites you keep running
- Every rule carried over, traced
Everything to run it
- The specs it was built from
- Architecture and API contracts
- Handover sessions with your team
Ready for agents
- The grounding layer for the new code
- MCP access for your coding agents
- Conventions agents can follow
Working code early, and more every week.
The build starts from a complete, verified map of your existing system, so every week goes into building.
Week 1
Grounding sample
The grounding layer on a sample of your code, so you see what we can do on your own system.
Then
The grounding layer
Every rule and flow of your existing system, verified and ready to build from.
Then
Module by module
New code delivered in increments, each one tested against the old.
Throughout
You see it
Progress, coverage and test results in the Swimm platform, every week.
From the stack you have to the one you want.
When the application you need means a new stack, these are the paths we follow.
Business logic carried over intact, with tests to show nothing changed that shouldn't.
Split along the real dependencies, one service at a time, while the system keeps running.
Rebuilt in the language your team hires for, with every rule extracted and verified first.
Running something else? Tell us on the scoping call and we'll confirm the path for your code.
Our engineers and agents, side by side with yours.
A pod of forward-deployed engineers runs the build. Agents do the heavy lifting on top of the verified map, and our engineers review every change.
Hybrid teams
Your engineers join the pod, so knowledge of the new code stays in-house.
Experts in the loop
Every module is reviewed by people before it's handed over.
Yours from day one
You own what we build; we're there when you want to go further.
Modules
New application, module by module
Your new code, and a live map of it.
The new application is yours, in your repos. Its map lives on in the Swimm platform, in sync with every commit, so your engineers and agents keep building on solid ground.
- Engineers see every module, rule and test in one place.
- Coding agents work on the new code with verified context over MCP.
- Every change stays traced to the rules it touches.
You own what we build; we're there when you want to go further.
Get our open-source COBOL modernization when it's published.
We're modernizing a public COBOL application start to finish and publishing every step: the map, the rules, the new code and the tests. Leave your email and we'll send it when it's live.
An open-source COBOL estate
From COBOL programs and copybooks
To a modern stack, with parity tests
Written up step by step, like a lab journal
Frequently asked questions
Do you write the new code yourselves?
Yes. Our pod of forward-deployed engineers builds it with our agents, and your engineers can join the team. We deliver working code, not a recommendation.
How do we know the new code does what the old code did?
Parity tests compare the new behaviour with the old for each module we hand over, and every rule from the old system is mapped and verified before the build starts.
Can we keep the system running during the move?
Yes. We deliver module by module, so the old and new systems can run side by side until each part is switched over.
Who owns the code?
You do. It lives in your repos from the first commit. You own what we build; we're there when you want to go further.
How is it priced?
By the size and complexity of the system and the pace you need. The grounding sample ends with a firm proposal: scope, team and dates.
The application you need doesn't have to wait.
30 minutes with our team. Bring the date you're working to.