Posteo vs Proton Mail Comparison

Feature	Posteo Visit →	Proton Mail Visit →
Overview
Rating	6.1	8.5
Pricing	$1.00/moStandard (individual, monthly) Show billing detailsHide billing details Standard (individual, monthly): EUR 1/month, prepaid credit, no annual commitment	$4.99/moMail Plus (individual, annual) $12.99/moProton Unlimited (individual, annual) Show billing detailsHide billing details Mail Plus (individual, annual): $59.88/year at renewal ($47.88 first year with the introductory rate) Proton Unlimited (individual, annual): $155.88/year at renewal ($119.88 first year with the introductory rate)
Free tier	Paid only	Limited free tier Show detailsHide details 1 GB storage, 1 email address, 150 messages/day, 10 hide-my-email aliases, no custom domain
Established	2009	2014
Platforms	Not specified	WindowsmacOSLinuxAndroidiOS
Privacy
Jurisdiction	Germany Show detailsHide details Posteo e.K. (a registered sole proprietorship), Methfesselstr. 38, 10965 Berlin. Registered at the Handelsregister Berlin-Charlottenburg, HRA 47592 B. Founded and owned by Patrik and Sabrina Löhr, self-financed with no external investors or debt.	Switzerland Show detailsHide details Proton AG, Route de la Galaise 32, 1228 Plan-les-Ouates, Geneva. Since June 2024 the primary shareholder is the non-profit Proton Foundation, also based in Geneva. Proton Europe sàrl (Luxembourg) is the designated EU GDPR representative.
Independent security audit	Cure53 2017 Show audit detailsHide audit details Posteo web application, including Calendar and Notes (a separate, earlier Cure53 test in April 2015 covered Crypto Mail Storage specifically)	Securitum 2021 Show audit detailsHide audit details Source-code security audit of the redesigned Proton Mail web client and Proton Calendar, prior to release
Source code	Partly open source	Fully open source
Zero-access encryption	Yes	Yes
Intra-provider E2EE	No	Yes
External PGP	Native	Manual import
Past data breach	No	No
Telemetry	No telemetry	On unless you opt out
Features
Hosting	Cloud	Cloud
Custom domain support	No	Yes
Aliases	Limited	Unlimited
Anti-spam approach	Described by Posteo only as a 'highly efficient spam and virus filter' — no further technical methodology is publicly documented.	PhishGuard flags spoofing and phishing using sender authentication (SPF/DKIM/DMARC) and metadata such as headers, link URLs and attachment hashes, not message content, since encryption prevents Proton from reading it; a machine-learning model retrains on user feedback (marking spam/phishing or rescuing a message from spam).
Bundled services	CalendarAddress BookNotes	CalendarDriveVPNPass