The core systems that still run your business are the ones nobody fully understands and nobody wants to touch, and they block everything else on the roadmap. We modernise them without stopping them.
Days
to read an estate from its code and map what it does
Instead of months of interviews
100%
of capabilities traced from the old system to the new one
How we work
0
big-bang cutovers. Old and new run in parallel until the outputs match
How we work
1
rollback path kept open through every cutover
How we work
Pro tip:Start with Code Analysis, fixed price.
A map of what the system does, how it is built and where it is fragile, delivered in days.
About the solution
Most of the cost of a modernisation used to go into working out what the old system actually does. AI reads a large codebase in days and pulls out the rules buried in it, so the rebuild starts from facts instead of guesses. Senior engineers decide what is kept, replaced or retired.
Let’s talkBusiness rules, data flows and hidden dependencies extracted from the code: what the system does, how its parts connect and where the risks sit.
What stays, what gets replaced and in which order, with each increment scoped and priced before it starts.
Each capability rebuilt on a modern stack and traced from the old system to the new one, with characterisation tests generated from the legacy code.
Data, reports and integrations moved with every difference reconciled. Data handling and regulatory exposure checked in every increment.
Old and new run side by side until the outputs reconcile. Cutover with the rollback path kept, then the old platform switched off and its licences freed.
Existing AI features moved to Claude, with evals showing the results hold before the switch.
As an Anthropic certified partner, we take Claude from the first pilot to everyday use across your teams.
Features running on another model or provider moved across, with evals showing results hold before the switch.
MCP connectors on top of the legacy estate, so teams get AI value before the replacement lands.
Claude Code maps the legacy estate and writes characterisation tests. Senior engineers review every conclusion.
Written spec, plan, build and verification against real data, with agents doing the volume and engineers the judgement.
Is that you
A measured baseline and a ranked opportunity portfolio.
The budget for new work goes to keeping the old system running.
Releases are rare because nobody trusts the tests.
The people who built it have left, and nothing written down matches the code.
Every AI initiative stalls
at the same integration.
Nobody can say what would break if the system were switched off.
How it works
What the system does, how it is built and where it is fragile, taken from the code itself.
Target architecture and increments, each scoped and priced before it starts.
Each capability traced old to new, data and regulatory exposure checked every time.
Old and new run side by side until the outputs match. Rollback kept.
Old platform off, licences freed, knowledge transferred. We run it if you want us to.
How a modernisation runs · increments with a parallel run.
Why it holds
What changes
| Question | Usual answer | Our answer |
|---|---|---|
| What does the old system do? | Workshops and interviews. | Read from the code, then confirmed with the people who use it. |
| How do we know nothing was lost? | User complaints after go-live. | Every capability traced from old to new, with tests that prove it. |
| When do we switch over? | One planned weekend. | When old and new produce the same results side by side. |
| What if it goes wrong? | Fix forward under pressure. | A rollback path kept open through cutover. |
| What about data and regulation? | Reviewed at the end. | Checked in every increment. |
| When do we stop paying twice? | Often never. | The old stack switched off and its licences freed. |
| Who can maintain it afterwards? | Whoever wrote it. | Your team, with docs, tests and decisions in your repository. |
What you own
A map of what the system does, how it is built and its risks.
Target design and the migration plan.
Characterisation and regression test suites.
The new platform in your cloud, with run books and decision records.
Our work
Recovering six years of system knowledge, rebuilding integrations and progressively migrating live traffic.
Explore case: Untangling Retail IntegrationsEngagement
Same engineers, either shape. Take a fixed piece of work, or add senior people to your own team.
For the analysis and for each increment, since every increment has a clean definition of done.
For a full modernisation programme.
Your own migration team leads, with our senior engineers inside it.
For long programmes, with run and support under Product & Platform Engineering.
Tell us what you're working on. A senior expert will get back to you.
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