Euro-Office: The Open-Source Microsoft Office Alternative — and How to Build a Whole Microsoft-Free Stack

On 9 June 2026, a coalition of European technology companies released the first stable version of Euro-Office — a free, open-source office suite pitched as a genuinely sovereign alternative to Microsoft 365 and Google Workspace. It handles documents, spreadsheets, presentations and PDFs, runs in the browser, and reads and writes the Microsoft formats your team already lives in (DOCX, XLSX, PPTX) as well as Open Document Format files (ODT, ODS, ODP).

That alone is interesting. But the more useful question for a UK business owner is the bigger one sitting behind it: how much of your reliance on a single American vendor could you actually unwind — and should you? Below is the honest version, including where Euro-Office is genuinely ready and where it isn't yet.

Why was Euro-Office created?

For years, European organisations have run their day-to-day work — email, documents, file storage, video calls — on software owned and operated by a small number of US giants. That was a convenience trade-off most people never thought twice about. Recent geopolitical wobbles changed the conversation. When the legal basis for transferring data across the Atlantic keeps getting challenged in court, and when access to critical tools can in theory be affected by decisions made in another country's politics, "we'll just use Microsoft" stops feeling like a non-decision.

Euro-Office is the open-source response. It's backed by an industry consortium that includes Nextcloud, hosting provider IONOS, and others such as XWiki, OpenProject, Eurostack, Open-Xchange, Abilian, BTactic and Soverin. As Nextcloud's CEO Frank Karlitschek put it, Europe has had the technical building blocks for years — what was missing was an initiative to assemble them into one coherent, trustworthy product. It's built on the open-source OnlyOffice document engine, which is why format compatibility with Microsoft files is solid out of the gate.

The point isn't anti-American. It's about control: knowing where your data physically lives, under whose laws it falls, who can be compelled to hand it over, and whether you could keep running if a commercial or political relationship soured.

The case for keeping your data outside the USA

"Where is our data, legally?" is a question more UK boards should be able to answer. Here's why it matters in plain terms.

• US law can reach US-operated data wherever it sits. Under legislation like the US CLOUD Act, a US-headquartered provider can be compelled to produce data it controls — even when that data is stored on servers in Europe. Choosing a European-operated stack narrows that exposure.
• Cross-border transfer rules are a moving target. The legal frameworks that permit EU/UK–US data transfers have been struck down and rebuilt more than once. Keeping personal data on European infrastructure removes a whole category of compliance risk and paperwork from your plate.
• GDPR / UK GDPR accountability is yours. You remain the data controller no matter whose software you use. Being able to point to where data is processed — and to open-source code you or your provider can actually inspect — makes demonstrating compliance far easier.
• Resilience and leverage. If everything runs through one vendor's account, a billing dispute, policy change or outage can take your whole business offline at once. A more independent stack means no single switch can turn you off.
• It's increasingly a sales requirement. Public-sector tenders and larger clients now routinely ask where data is hosted and processed. "In the UK / EU, on open standards" is becoming a competitive advantage, not just a compliance box.

What does Euro-Office cost?

This is the part that surprises people: the software itself is free and open source. The code is published openly on GitHub, so there's no per-seat licence fee to use it. That's a structurally different model from Microsoft 365, where the cost grows with every user you add, every year, forever.

What you actually pay for is where it runs and who looks after it:

• Self-hosted: run it on your own server or a European cloud and your only costs are hosting and the time (yours or a partner's) to set it up and maintain it. No licence fees at all.
• Managed: access it through a provider — for example bundled into Nextcloud Hub or IONOS's managed Nextcloud — and you pay a predictable hosting/subscription fee, typically well below equivalent Microsoft 365 pricing, with the data still held in Europe.

The honest takeaway: Euro-Office can take per-seat office licence costs close to zero, but "free software" is never "free to run." The saving is real, but the right way to capture it is to budget for hosting and support rather than licences. For a 20- or 50-person business, that maths often works out very favourably — and it's exactly the kind of comparison we'll run for you honestly, including the cases where staying on Microsoft is the better call.

Completing the stack: a Microsoft-free toolkit

An office suite is one piece. The reason most businesses feel locked in is that Microsoft sells the whole stack — email, files, chat, video, the operating system. The good news is there's a mature, self-hostable open-source equivalent for nearly every part of it. Here's how the pieces map across.

Documents & office — Euro-Office / OnlyOffice / LibreOffice

Replaces Word, Excel and PowerPoint. Euro-Office (web-based collaboration) or LibreOffice (the long-established desktop suite) cover the vast majority of everyday document work, with full Microsoft-format compatibility.

File storage & sync — Nextcloud

Replaces OneDrive and SharePoint. Nextcloud gives you file sync, sharing, versioning and real-time collaboration, hosted on your own infrastructure or a UK/EU provider. It's the backbone most sovereign stacks are built around, and Euro-Office plugs straight into it.

Team chat — Mattermost

Replaces Microsoft Teams (chat). Mattermost is a self-hostable team messaging platform — channels, direct messages, file sharing and integrations — that looks and behaves much like Teams or Slack, but where you own the server and the message history.

Email & calendar — Open-Xchange / Mailcow / Proton

Replaces Outlook / Exchange Online. European providers like Open-Xchange and privacy-first options, or self-hosted suites such as Mailcow, deliver shared mailboxes, calendars and contacts with your data held in Europe.

Video meetings — Jitsi / Nextcloud Talk

Replaces Teams / Zoom calls. Jitsi Meet and Nextcloud Talk provide browser-based video conferencing and screen sharing you can run on your own server — no account with a US platform required.

Operating system — Linux

Replaces Windows. Modern desktop Linux distributions (Ubuntu, Linux Mint, Fedora and similar) are now genuinely approachable for everyday office users, run happily on older hardware, and remove both licence costs and a layer of vendor dependency. This is usually the biggest change-management step, so it's the one to phase in carefully rather than overnight.

Project & knowledge — OpenProject & XWiki

Replaces Microsoft Project, Planner and parts of SharePoint. OpenProject handles project planning and task tracking; XWiki gives you a collaborative internal wiki and knowledge base — both self-hostable, both already part of the Euro-Office consortium.

Why data independence matters for every business

It's tempting to file "digital sovereignty" under "something for governments and big banks." It isn't. The principle scales all the way down to a ten-person firm in Manchester:

• You're never one account suspension from disaster. Own your storage, email and chat, and no single external decision can lock you out of your own business.
• Predictable, often lower costs. Open-source tools replace ever-climbing per-seat licences with hosting and support you can budget — and that don't punish you for growing.
• Open standards mean no lock-in. Data in open formats can always be moved, exported and read years from now, regardless of any one vendor's roadmap or pricing.
• Easier compliance and stronger trust. Knowing exactly where your clients' data lives — and being able to say so — is becoming a baseline expectation, not a nice-to-have.

Data independence isn't about distrusting any one company. It's about your business not being wholly dependent on a single one — keeping the choice, the cost and the control in your own hands.

Let's talk it through

Euro-Office and the wider open-source stack are genuinely exciting — but the right answer for your business depends on your team, your apps and your appetite for change. At Aspire we'll give you the straight version: what's ready today, what would save you money, what's worth leaving on Microsoft for now, and how to move without disrupting the people doing the actual work. We support both worlds, so there's no agenda to sell you one over the other.

If reducing your Microsoft dependency — or just understanding where your data really sits — is on your mind, get in touch and we'll map out a sensible plan together.

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