European Email and Groupware: Microsoft 365 Alternatives

Microsoft 365 is the default in many companies. At the same time, more and more executives and IT managers are asking whether email, calendars and contacts could just as well be hosted by a European provider. This article presents common European alternatives, compares them neutrally and shows what to look out for when switching.

Why companies look for alternatives

The reasons vary. Commonly cited ones include:

• Data protection and legal framework: with the EU Data Boundary, Microsoft has committed to storing and processing customer data for core cloud services within the EU and EFTA, and announced its completion in February 2025. Microsoft nevertheless remains a US company subject to US law. Some companies therefore prefer providers that are subject only to European law.
• Independence: bundling every service with one large provider makes you dependent on its pricing and licensing policy.
• Actual needs: many small companies mainly use email, calendars and file storage from a large suite.

Whether switching makes sense depends on your situation. A European provider is not automatically more secure, and Microsoft 365 is not automatically non-compliant. What matters is a well-reasoned assessment.

Providers at a glance

The following providers are headquartered in Europe and offer solutions for businesses (as of November 2026). The list is not exhaustive and is not a recommendation of any particular product.

mailbox.org

mailbox.org is operated by Heinlein Hosting GmbH, based in Berlin. In addition to email, calendar and address book, higher business tiers include office features, video conferencing and cloud storage. According to the provider, its services run in data centres in Berlin. Businesses get a central administration interface.

Tuta

Tuta is a product of Tutao GmbH in Hanover. Its focus is end-to-end encryption, meaning only sender and recipient can read the content. The business plan includes email, calendar and contacts with custom domains. It is used through the provider's own apps and web interface. Tuta's business page does not mention IMAP access for arbitrary email clients, which matters if you want to keep using Outlook or Thunderbird.

Proton

Proton Mail is offered by Proton AG, based in Geneva. Switzerland is not part of the EU but benefits from an EU Commission adequacy decision on data protection. Proton also focuses on end-to-end encryption and offers business plans. Desktop clients such as Outlook or Thunderbird can be connected on paid accounts via the add-on Proton Mail Bridge.

Nextcloud

Nextcloud GmbH is based in Stuttgart. Nextcloud is an open source platform for files and collaboration that you can run yourself or use through a hosting provider. Its groupware bundle includes a mail client, calendar and contacts. Note that, according to the vendor, Nextcloud does not include a mail server itself, so you also need an IMAP and SMTP server.

IONOS

IONOS SE is headquartered in Montabaur, Germany. It offers traditional email packages with a custom domain, a Nextcloud-based workspace and, as a partner, Microsoft 365. For companies looking for a large German provider with a broad portfolio, IONOS is therefore an option.

Neutral comparison

This table is a rough overview. Features and plans change, so check details directly with the provider before deciding.

What to look for when choosing

• Features: do you need only email, calendar and contacts, or also file storage, office apps and video conferencing?
• Compatibility: which programs and smartphones do your employees use? Does the provider support open standards such as IMAP, CalDAV and CardDAV?
• Encryption: end-to-end encryption strongly protects content but can limit features such as server-side search or integration with third-party software.
• Administration: is there central management for users, groups and mailboxes?
• Contract and GDPR: does the provider offer a data processing agreement?
• Migration: are there tools or support for moving existing mailboxes, calendars and contacts?
• Support: what support hours and channels are available for business customers?

What about Word, Excel and Teams?

Switching email and groupware does not necessarily mean giving up Microsoft Office. Many companies separate the two: email runs with a European provider, while office applications continue as standalone licences or are replaced by alternatives. It gets harder when Teams, SharePoint and Outlook are tightly integrated. In that case, clarify in advance which features are actually used day to day and what alternatives are available for them.

Steps for an orderly switch

1. Take inventory: count mailboxes, distribution lists, shared calendars and forwarding rules.
2. Check dependencies: identify applications closely tied to your current system, such as CRM, phone system or scanners that send email.
3. Test providers: use trial accounts and test day-to-day use with a small group.
4. Plan the migration: set a cut-over date and lower the TTL of your DNS records in advance, which is how long records are cached.
5. Update DNS: adjust MX, SPF, DKIM and DMARC for the new provider.
6. Move data: transfer mailboxes, calendars and contacts and spot-check the results.
7. Brief employees: explain the new apps and logins before the cut-over date.
8. Cancel the old service: only once everything works, cancel the previous service and archive old data.

Managed email and groupware from Simplify Data

Simplify Data offers managed email and groupware for small and mid-sized companies. We help you choose, handle setup, migration and DNS configuration, and look after ongoing operations. View business mail

Sources

• Microsoft: EU Data Boundary completed
• mailbox.org: business offering (German)
• Tuta: business plans
• Nextcloud: Groupware
• Proton: Proton Mail Bridge