European alternatives to Microsoft 365
Microsoft 365 is standard in many organizations, but raises questions about data sovereignty and US law. European alternatives combine email, calendar, files and office – partly self-hostable.
Why look for an alternative?
Reasons include digital sovereignty, EU data storage and the desire for independence from a US provider – especially in the public sector and education.
What to look for in an alternative
- Coverage of email, calendar, files and office
- EU data residency or self-hosting
- Collaboration and team features
- DPA and compliance support
- Migration and operational effort
The best European alternatives at a glance
Sorted by suitability as a replacement for the tool you searched. The Sovereignty Score independently rates how European and data-sovereign a provider is – so the two values can differ.
Open-source, self-hostable collaboration platform from Germany – files, calendar, office and more.
German business email and groupware with servers in Berlin – based on Open-Xchange, ISO 27001 and BSI C5.
Independent Swiss cloud and hosting provider with own data centers – from web hosting and email to public cloud, 100% green electricity.
Swiss privacy suite with end-to-end encrypted email, calendar, drive, password manager and VPN.
Comparison table
| Providers | Fit | Sovereignty | Headquarters | Open Source | Self-hosting | EU hosting | Pricing |
|---|---|---|---|---|---|---|---|
| Nextcloud | 84 | 90 | Germany | Open source (AGPLv3) / enterprise support | |||
| mailbox.org | 76 | 84 | Germany | from 1 € / Monat | |||
| Infomaniak | 74 | 86 | Switzerland | Web hosting / cloud (pay-as-you-go) | |||
| Proton | 70 | 82 | Switzerland | from 3,99 € / Monat |
The top providers in detail
Nextcloud is the leading open-source alternative to cloud suites such as Google Workspace or Microsoft 365. Self-hosted or operated through a European provider, Nextcloud combines file sharing, calendar, contacts, video calls and office editing. Full data sovereignty is therefore central. The Community Edition (AGPLv3) is free for unlimited users – only the costs of your own server apply; Nextcloud Enterprise with support starts at around €69 per user per year (from 100 users).
Strengths
- Full data sovereignty through self-hosting
- Open source with a large app ecosystem
- Covers files, groupware and office
Weaknesses
- Self-hosting requires operation and maintenance
- Performance depends heavily on your own infrastructure
mailbox.org (Heinlein Group) offers ad-free email mailboxes with calendar, contacts, office and video conferencing based on the open-source OX App Suite (Open-Xchange). The servers are located exclusively in two redundant Berlin data centers; the service is ISO/IEC 27001 certified and attested according to BSI C5, and a TÜV-certified data protection officer monitors compliance. Unlike purely encrypted services, mailbox.org supports standard protocols (IMAP/SMTP/CalDAV) as well as PGP and S/MIME, making it a good Microsoft 365-like alternative. The Light plan starts at €1 per month, Standard at €3.
Strengths
- Standard protocols (IMAP/SMTP/CalDAV), PGP & S/MIME, groupware
- Servers exclusively in Germany, ISO 27001 + BSI C5
- Affordable from €1/month, ad-free
Weaknesses
- No continuous end-to-end encryption like Tuta/Proton
- Interface feels less modern
Infomaniak from Geneva is one of the best-known independent European hosting providers and is controlled by its own employees. The company operates its own data centers in Switzerland (Geneva and Winterthur); according to the provider, data never leaves Switzerland and is processed with open-source or self-developed software. Infomaniak is ISO/IEC 27001 certified (plus ISO 14001, 50001, 9001), runs on 100% renewable energy and has been climate-neutral since 2007. The offering ranges from web hosting and the kSuite groupware (alternative to Google Workspace) to OpenStack-based public cloud.
Strengths
- Own Swiss data centers, data does not leave Switzerland
- ISO 27001 plus ISO 14001/50001/9001, 100% green electricity
- Broad offering: hosting, email/kSuite, public cloud
Weaknesses
- Headquartered in Switzerland (EFTA), not in the EU/EEA
- Not open source
- Public-cloud ecosystem smaller than with hyperscalers
Migration effort
| Providers | Migration effort | Fit |
|---|---|---|
| Nextcloud | high | 84/100 |
| mailbox.org | medium | 76/100 |
| Infomaniak | medium | 74/100 |
| Proton | medium | 70/100 |
When switching pays off
Nextcloud (where applicable with ONLYOFFICE/Collabora) plus a European email service such as mailbox.org forms a sovereign Microsoft 365 alternative. For public authorities and schools, this is a proven path.
When to stick with your current tool
If your organization is deeply integrated into Teams, SharePoint and the Office desktop apps, migration is a strategic project that requires good planning.
Frequently asked questions
Can a public authority switch completely to Nextcloud?
The Sovereignty Score is an editorial orientation aid, not legal advice. How we rate.