Collabora Online vs OnlyOffice: Which Self-Hosted Office Suite After the Euro-Office Fork?

The self-hosted office suite space just got very interesting. A European consortium — Nextcloud, IONOS, and Proton among them — forked OnlyOffice into "Euro-Office," citing transparency concerns, closed development practices, and the project's Russian development team. OnlyOffice responded by suspending its 8-year partnership with Nextcloud and alleging license violations.

Whether or not Euro-Office takes off, the drama has done one thing clearly: it's made people re-evaluate their self-hosted office suite choice. If you're in that camp, here's where Collabora Online and OnlyOffice actually stand in 2026.

The Quick Overview

Microsoft Office Compatibility

This is usually the deciding factor, and here's where they diverge most.

OnlyOffice uses OOXML (DOCX, XLSX, PPTX) as its native format. It doesn't convert your files — it reads and writes Microsoft formats directly. If your team works primarily with .docx files and needs pixel-perfect compatibility with Microsoft Office, OnlyOffice is hard to beat. Complex spreadsheets with macros, presentations with embedded media, and documents with advanced formatting all render more faithfully.

Collabora Online is built on LibreOffice and prioritises ODF (Open Document Format). It handles Microsoft formats well — but "well" isn't "perfectly." Complex layouts sometimes shift, and advanced Excel formulas may behave differently. Where Collabora shines is in ODF support: if your organisation has standardised on open formats (common in EU government and education), Collabora preserves those documents flawlessly.

Infrastructure Requirements

This matters more than most people realise.

Collabora Online runs on a single container with a clean architecture that keeps documents server-side. You can run it on a 1 GB RAM server. Deployment is straightforward — one Docker container, one reverse proxy config, done.

OnlyOffice Document Server requires five separate services: PostgreSQL, RabbitMQ, Nginx, Redis, and the document server itself. Minimum practical RAM is 4 GB, and the complexity scales with your user count. It's a heavier stack to operate and maintain.

If you're running a small team and want minimal infrastructure overhead, Collabora is significantly lighter. If you have dedicated ops capacity and need the feature set, OnlyOffice's complexity is manageable.

The Licensing Question

This is where the Euro-Office drama becomes relevant.

Collabora Online is fully open-source under MPL 2.0. No user limits, no feature restrictions on the community edition. You can fork it, modify it, contribute to it — the development process is transparent and welcoming.

OnlyOffice uses an open-core model under AGPL v3. The Community Edition is capped at 20 concurrent connections. Beyond that, you need a commercial license. The Euro-Office consortium specifically cited OnlyOffice's closed development practices — contributing to the codebase is described as "impossible or heavily discouraged," and build instructions are allegedly "unreliable or broken."

If open-source principles, sovereignty, and the ability to contribute matter to your organisation, Collabora has the edge. If you just need a working office suite and don't plan to modify the code, OnlyOffice's licensing model is fine for most use cases.

Real-Time Collaboration

Both support simultaneous editing, but the experience differs.

OnlyOffice offers a smoother real-time collaboration experience with inline commenting, page history, version control, and a UI that feels close to Google Docs. It also supports 40+ integrations with platforms like Nextcloud, Odoo, and Confluence.

Collabora Online offers collaboration with more granular permissions and workflow management. The editing experience is functional but feels slightly more traditional — closer to desktop LibreOffice than to a modern web-native editor.

Deploy on Elestio

Both are available on Elestio with one-click deployment:

• Collabora Online on Elestio — Starting at $16/month (2 CPU, 4 GB RAM, 60 GB NVMe)
• OnlyOffice on Elestio — Starting at $29/month (4 CPU, 8 GB RAM recommended)

Elestio handles SSL, backups, updates, and monitoring. For custom domain setup, follow the official Elestio documentation.

The Bottom Line

• Pick Collabora Online if: You value open-source principles, need low infrastructure overhead, work primarily with ODF formats, or need unlimited concurrent users without a commercial license. Also the safer bet for EU sovereignty requirements.
• Pick OnlyOffice if: Microsoft Office compatibility is your top priority, you need a modern real-time collaboration experience with AI features, and your team is under 20 concurrent users (or you're prepared to license the enterprise edition).

The Euro-Office fork adds a third option to watch — but it's a preview with a 1.0 release expected this summer. For now, Collabora and OnlyOffice remain the two proven choices. Pick the one that matches your format requirements and your values.

Thanks for reading ❤️ See you in the next one 👋