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vsMicrosoft Outlook

grommunio Web vs Microsoft Outlook

Last updated October 2026

Looking for a European alternative to Microsoft Outlook? Here's how grommunio Web compares, on EU hosting, GDPR and what it does.

Our pick for a European buyer: grommunio Web. We weight data residency, GDPR and EU jurisdiction above everything else — that is the constraint this directory exists to solve.

grommunio Web
Microsoft Outlook
What it is
Open-source Exchange alternative with email, calendar, chat and video in one web client
not established
Headquarters
🇦🇹 AT
No
EU data residency
Yes, for all customers
not established
DSGVO / GDPR
Yes
not established
Certifications
No
not established
Price from
€1.99/user/mo
not established
Free plan
Yes
not established
Open Source
Yes
not established
Ratings
No
No
Integrations
WebDAV, Seafile, OpenStreetMap, OnlyOffice, Jitsi +7
not established

We have not yet completed our own research on Microsoft Outlook; rows above show only what we can evidence. Check the vendor for specifics.

Where each one wins

grommunio Web

Strengths

  • +Strong Outlook and Exchange compatibility via MAPI/HTTP, EWS, ActiveSync, IMAP, CalDAV/CardDAV
  • +Responsive performance compared to Zimbra in high-volume mailbox tests
  • +Groupware features like shared mailboxes, public folders, calendars and contacts
  • +Migration tools for onboarding existing data

Limitations

  • −Outlook category synchronization issues across multiple clients (colors missing in grommunio Web)
  • −Community Edition limited to five users, paid subscription required beyond that

Microsoft Outlook

Review sentiment not yet compiled.

Data residency & compliance

grommunio Web
Microsoft Outlook
EU data residency
Yes, for all customers
not established
Transfer mechanism
Not required — data stays in the EU
not established
DPA
not established
not established
Sub-processors
not established
not established
Certifications
No
No

Pricing

grommunio Web

  • Community Free up to 5 usersCommunity self-support · No vendor support
  • Basic €1.99 per user / month, from 6 usersComplete grommunio platform · All features included
  • Plus €3.99 per user / month, from 6 usersComplete grommunio platform · All features included
  • Business €5.49 per user / month, from 50 usersComplete grommunio platform · All features included
  • Enterprise Custom from 1,000 usersComplete grommunio platform · All features included

Plans differ by user count and support level. Online demo and trial version available for evaluation.

Microsoft Outlook

No published pricing we could verify.

Features

grommunio Web

Mail
Webmail with S/MIME and OpenPGP signing and encryption, Outlook-compatible color categories, Sticky notes on messages, BIMI sender logos
Calendar
Shared calendars and delegation, Free/Busy scheduling suggestions, Invitations with participant tracking, Recurring events with exceptions
Contacts, tasks and notes
Contact and address-book management, Task and task-request support, Notes
Collaboration plugins
Files: browse, upload, preview, share and attach documents, Chat: direct and channel-based messaging with file sharing, Meet: start video meetings or add meeting links to appointments
Sharing and access
Shared folders and mailboxes, Permissions, Delegate access

Microsoft Outlook

Feature breakdown not yet compiled.

See grommunio Web →More Microsoft Outlook alternatives