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Custom software · Legacy modernisation

Replace the system nobody dares to touch

Every company past a certain age has one: the system that runs everything and terrifies everyone. We modernise incrementally — strangler-pattern replacements, verified data migration and bridges that keep both worlds in sync — so the business never stops while the risk drains out of it.

What modernisation covers

From the honest audit to the day the old servers are finally switched off.

Technical audit & roadmap

What to keep, what to wrap, what to replace — an honest map of the system, priced phase by phase.

Strangler-pattern rebuilds

New modules take over one capability at a time behind a stable interface, with rollback at every step.

Data migration, verified

Reconciled totals, counts and spot checks between old and new — migration you can show an auditor.

Bridges & coexistence

APIs, file drops and event feeds that keep old and new consistent for as long as both must live.

How we de-risk a system replacement

Big-bang rewrites fail for structural reasons. This is the structure that doesn't.

01

Audit what exists

Code, data, integrations and the undocumented behaviour the business secretly depends on. The audit names what's worth keeping.

02

Wrap it in interfaces

A stable API layer around the legacy core — so new modules, integrations and tools stop depending on its internals.

03

Replace piece by piece

Each capability moves to the new system behind the same interface, runs in parallel, and cuts over only when the numbers match.

04

Decommission deliberately

The old system is switched off module by module — licences, servers and risk retired on a schedule, not a prayer.

What you hold at each phase

Every phase ends with something standalone — you can stop at any of them and be better off than you started.

Audit report & phased roadmapScope, risk and cost per phase — before you commit to any of it
Parallel-run verification reportsOld vs. new, reconciled in writing before each cutover
Migrated data with an audit trailEvery record accounted for, transformations documented
Documentation the old system never hadArchitecture, decisions and runbooks — in writing this time
90-day warranty per phaseDefects fixed free after each acceptance

Common questions

Can this really be done with zero downtime?

Phased cutovers with parallel runs mean the business keeps working throughout. Individual cutovers happen in maintenance windows measured in minutes — and every one has a tested rollback.

Rewrite or modernise — how do we decide?

The audit decides, honestly. Sometimes the answer is "keep the core, rebuild the edges"; occasionally a specific part deserves a rewrite. A big-bang full rewrite is almost never it, and we'll be the first to say so.

The system runs on technology nobody here knows anymore. Is that a problem?

It's the usual case. The wrap-first approach means we rarely need to change the old code at all — we contain it behind interfaces, and the new system grows in technology your future hires already know.

How long does modernisation take?

It's phased by design: the first capability typically moves within a quarter, and each phase delivers standalone value. You can stop after any phase and keep a system that's strictly better than where you started.

Case study · AI infrastructure · Dedicated team

A company's complete AI workloads, migrated from cloud APIs to on-prem hardware

An ongoing migration with no interruption to daily operations — workload by workload, with rollback at every step.

Read the case study →
on-prem
custom inference hardware
ongoing
engagement status

How much is the old system really costing?

Licences, workarounds, risk and the projects it blocks — the audit puts a number on it.