What can replace Outlook / Exchange Online.
3 European products that cover Outlook / Exchange Online fully or in part. None of them is a clone — where something is missing, it says so.
3 entries
mailbox.orgDE
A Berlin provider with mailbox, calendar, contacts and office on an OX base, open standards, your own domains, renewable power.
EU / EEAProvenEffort: Mediummailbox.org Replaces: Gmail · Outlook / Exchange Online
Proton MailCH
A Swiss provider bundling end-to-end encrypted mail, calendar, storage and VPN in one subscription, held by a foundation.
SwitzerlandProvenEffort: MediumOpen sourceCatchSwitzerland, not the EU. An adequacy decision exists, but Swiss surveillance law applies — and IMAP only works through the local bridge.
proton.me Replaces: Gmail · Outlook / Exchange Online
TutaDE
A Hanover provider with end-to-end encryption reaching into the search index, and a key generation already hardened against quantum attacks.
EU / EEAProvenEffort: MediumOpen sourceCatchNo IMAP and no SMTP. Outlook, Thunderbird and any script that sends mail must go through Tuta's own apps or its bridge.
tuta.com Replaces: Gmail · Outlook / Exchange Online
Every field, filter and catch lives in the full directory. Not a recommendation and not a review. A list with evidence, so you can draw up a shortlist. Ownership and headquarters change — verify whatever matters to you before you sign.
Data as of August 2026