Email providers

mailbox.orgvsPosteo

Both score similarly on sovereignty (84 vs 84). The right choice depends on the details below – open source, self-hosting, pricing and focus.

Score comparison

	mailbox.org	Posteo
Sovereignty	84	84
Privacy	85	92
Open Source	45	10
Business fit	76	66
Migration ease	65	60
Pricing transparency	80	90
Enterprise readiness	70	55

Features & facts

	mailbox.org	Posteo
Country	Germany	Germany
Open Source	No	No
Self-Hosting	No	No
Cloud/SaaS	Yes	Yes
EU data residency	Yes	Yes
DPA / AV-Vertrag	Yes	Yes
ISO 27001	Yes	Yes
Data location	Germany (Berlin, two redundant data centers)	Germany (Berlin, Frankfurt)
From	1 € / Monat	1 € / Monat
Founded	2014	2009

mailbox.org

Germany

German business email and groupware with servers in Berlin – based on Open-Xchange, ISO 27001 and BSI C5.

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

Posteo

Germany

Ad-free, green email service from Berlin with strong privacy – anonymous sign-up and payment, servers in Germany.

Strengths

Anonymous sign-up and payment, ad-free
Servers in Germany, ISO 27001, 100% green electricity
Simple flat plan (€1/month), annual transparency reports

Weaknesses

Not open source, no self-hosting
Focus on email/groupware, few business/team features
Comparatively little storage in the base plan

Choose mailbox.org if…

Freelancers and SMEs that want groupware instead of pure encryption
Public authorities and schools with sovereignty requirements

Choose Posteo if…

Privacy-conscious private users
Users who value anonymity and sustainability

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Scores are editorial orientation, not legal advice. Details are based on public provider information and are not independently verified.