Category: Collaboration
8 European alternatives to Microsoft Exchange Online — GDPR-compliant & EU-hosted.
Enterprise email and calendaring service
Facts
- Headquarters
- US (US)
- Category
- Collaboration
- Type
- Product
- GDPR-compliant
- No
- Open-source
- No
- Data hosting
- US, EU
Top EU-based & GDPR-compliant alternatives to Microsoft Exchange Online
- ONLYOFFICE↗
ONLYOFFICE is a Latvian office suite that was open source (AGPLv3) until version 9.4 (May 2026), when additional Section 7 terms were introduced requiring logo retention in forks while simultaneously denying trademark rights. The Free Software Foundation ruled this a prohibited further restriction under AGPLv3 Section 10, breaking OSI compliance. The software is now effectively source-available with restrictions.
LV · commercial
Frequently asked questions
What is the best European alternative to Microsoft Exchange Online?
It depends on your use case. Strong EU alternatives to Microsoft Exchange Online include grommunio, Infomaniak and Kolab. On this page you can compare 8 EU alternatives by jurisdiction, data residency and open-source status.
Are there open-source alternatives to Microsoft Exchange Online?
Yes. Open-source EU alternatives to Microsoft Exchange Online include grommunio, Kolab, Nextcloud and Open-Xchange. These keep your data fully under your own control and let you self-host if you want to.
Is Microsoft Exchange Online GDPR-compliant and where is the data hosted?
Microsoft Exchange Online is headquartered in US and hosts data in US, EU. Its GDPR compliance is limited or unclear. For full EU data residency the EU alternatives on this page usually offer more certainty.