Moving Off US Software: The Migration Guide
A practical framework for replacing US platforms with European and open-source alternatives — without the big-bang programme that eats two years and fails anyway.
Most migration programmes fail at the same step: the first one. They try to move everything, discover that everything is connected to everything else, and spend the budget discovering it. The organisations that succeed do something less heroic and more effective — they classify first, move the tier that matters, and let the commodity tier follow when the contract renewals make it cheap to do so.
Before anything else: classify by consequence
The most useful sovereignty exercise of 2026 was not a policy paper. It was Airbus moving roughly 900 applications — its “minimum viable company” — to a French cloud provider, while calmly keeping AWS, Salesforce and Workday for the tiers where the data matters less. The playbook generalises to any organisation:
- Classify by consequence, not by vendor. Which systems would genuinely hurt if a foreign jurisdiction could compel access to them, or switch them off? That list is shorter than you think, and it is the list that moves first.
- Procure on jurisdiction, not geography. A European data centre run by a US-headquartered company is still reachable by the CLOUD Act. Residency is where the disks are; sovereignty is whose law the operator answers to.
- Keep your options everywhere else. Sovereignty is a strategic choice about your critical tier, not a vow of poverty. Commodity workloads can live wherever the deal is best — as long as you can tell the difference, in writing, in your procurement scoring.
The six steps
Inventory
List every US-origin service in the estate: what data it holds, who uses it, what it integrates with, and — critically — when the contract renews. Renewal dates are your migration calendar; moving mid-contract is money you did not need to spend.
Classify
Sort the inventory into the critical tier (regulated data, crown-jewel IP, the systems that keep the organisation alive) and the convenience tier. Only the first tier needs a jurisdiction argument. The second needs a cost argument.
Choose replacements per workload
Match each workload to a European or open-source alternative — the alternatives catalogue covers the six most common, and the office-suite comparison shows the honest trade-offs. Prefer tools that read and write your existing file formats; format lock-in outlives vendor lock-in.
Pilot with real work
Give the replacement to a small, willing group for four to six weeks doing actual work — not a scripted demo. Write the success criteria down before the pilot starts, or the debrief becomes a referendum on change itself.
Run in parallel, then migrate
For anything critical, run old and new side by side until the new system has carried a full business cycle — month-end, payroll, audit, whatever your cycle is. Then migrate team by team. Big-bang cutovers are how migration programmes get their reputation.
Decommission and evidence
Export and archive the data, cancel the licence at renewal, and write down what moved, when, and where it now lives. The next audit — or the next regulator — will ask, and “we migrated last year” is not evidence.
What not to migrate (yet)
An honest guide has to say this: there are workloads where the US incumbents still win on capability, and pretending otherwise is how sovereignty programmes lose credibility with the people who have to use the tools. Deep Excel modelling, some specialist CAD and engineering software, and parts of the enterprise analytics stack have no like-for-like European replacement today. The answer is not to force a worse tool on your analysts; it is to move everything around those workloads so the remaining dependency is small, visible, and documented — and to re-check the market annually, because it is moving fast.
What it costs
Licensing is the visible number: European and open-source alternatives typically run 60–90% cheaper per seat, which the savings calculator will estimate for your headcount. The honest budget also includes migration effort, parallel running, and training — usually the difference between a migration that sticks and one that quietly reverts. What you get back is not just the licence saving: it is an estate whose legal exposure you can actually describe.
The failure modes
- The big bang. Migrating everything at once, on a date, with a countdown. Survivable for a five-person firm; reckless for anyone larger.
- No executive sponsor. Migration touches every department’s habits. Without someone senior absorbing the complaints, the programme dies at the first difficult week.
- Skipping training. The tools are not hard; they are different. An hour of structured introduction per team is the cheapest success factor in the whole programme.
- Treating it as ideology. The goal is an organisation that could change vendors if it had to — not a flag planted on a particular stack.
Where to start this week
Open a spreadsheet. List your US-origin services, their renewal dates, and the data classification of each. That single document — an afternoon’s work — is step one and half of step two, and it turns the sovereignty conversation from a posture into a plan. If you want a second pair of eyes on it, get in touch.
Start With the Inventory
Estimate the savings for your organisation, or ask about a migration assessment.