mailbox.org
EU verifiedGerman business email and groupware with servers in Berlin – based on Open-Xchange, ISO 27001 and BSI C5.
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.
Note on ownership: Operated by the Heinlein Group (Berlin), one of Germany's leading Linux/email specialists with more than 150 employees. Servers exclusively in two redundant Berlin data centers.
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
Best for
- • Freelancers and SMEs that want groupware instead of pure encryption
- • Public authorities and schools with sovereignty requirements
Less suited for
- • Users who want zero-access encryption
Sovereignty Score & weitere Bewertungen
The Sovereignty Score is an editorial orientation aid, not legal advice. How we rate.
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Sources & notes
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