Legacy system migrations
Move off the old system without losing what works.
Most businesses have one: the ageing system everything quietly depends on. The database the old developer built before he retired, the spreadsheet that's become mission-critical, the software that's out of support but 'still works'. It's risky to keep and scary to replace. I do this carefully: understand what the old system really does, rescue the data, rebuild on modern foundations, and run old and new side by side until you trust the switch. I've migrated systems for insurers and banks where downtime wasn't an option — the same discipline, applied to your business.
When this service makes sense
You probably need this if…
The person who built or understood your system has left, retired, or disappeared.
Your software is out of support, can't be updated, or only runs on one old machine.
A spreadsheet or Access database has grown into something the whole business leans on.
You want to modernise but can't afford the system going down while you do.
Your data is trapped in an old system that nothing else can talk to.
How I approach it
My approach, step by step.
- 01
Understand before touching
The most dangerous migrations start with a rewrite and end with 'why doesn't it do the thing it used to?'. I start by mapping what the old system actually does — including the undocumented quirks your business secretly relies on — so nothing important gets lost in translation.
- 02
Rescue the data first
Your records, history, and customer data come out clean, checked, and backed up before anything else changes. Where legacy data is messy — years of free-typed notes and inconsistent categories — I can use AI classifiers to make sense of it at a scale no one could by hand.
- 03
Migrate in stages, not a big bang
I move one piece at a time, starting where the risk or pain is worst. Old and new run side by side, results are compared against each other, and we only switch over when the new system has proven itself on your real work.
- 04
Leave you better off, not just newer
The end state is a modern, supported, documented system that other tools can connect to — and that any competent developer could pick up after me. The goal is to get you off the cliff edge permanently, not to make you dependent on a new stranger.
What you get
Concrete deliverables.
- A plain-English map of what your current system does, quirks included
- Your data extracted, cleaned, verified, and safely backed up
- A modern replacement built and proven alongside the old system
- A staged cut-over with no big-bang risk and no lost work
- Documentation and a handover so you're never trapped like this again
Typical timeline
Depends entirely on the system — some migrations take a couple of weeks, some run for months in careful stages. Like bespoke work, it's charged at a day rate with a two-week minimum. I scope the old system in a free first call and give you a staged plan with an estimate before anything is touched.
Common questions
What clients usually ask.
Will the business have to stop while we migrate?
No — that's the point of doing it in stages. The old system keeps running while the new one is built and proven beside it. The switch happens piece by piece, at quiet moments you choose, and we can roll back at any stage if something isn't right.
What if nobody understands the old system anymore?
That's the most common starting point, and it's fine. I work it out from the system itself — the data, the code if there is any, and how your team actually uses it day to day. Reverse-engineering undocumented systems is a normal part of this work, not a blocker.
Can you migrate the data without losing anything?
Data comes first, before any rebuilding: extracted, checked against the original, and backed up. Where old data is messy or inconsistent, I clean it as part of the move — with AI classifiers doing the heavy lifting on big, messy datasets — and you review anything ambiguous rather than me guessing.
What does a migration cost?
It's day-rate work with a two-week minimum, and the honest answer is it depends on the system. What I won't do is quote blind: I scope the old system first, then give you a staged plan where each stage delivers something on its own — so you're never far in without value to show for it.
Want to talk about legacy system migrations?
Tell me what you're trying to do. It's me who reads your message, and I'll reply within one business day.
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