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Proton Mail vs Kolab Now: catalog facts
Proton Mail	Kolab Now
Freemium Free accounts work in the mobile and web apps; the desktop apps are offered as a free…	Paid Paid subscription service.
Windows, macOS, Linux, Android, iOS, Web	Web
End-to-end encrypted email by default Apps for iOS, Android, macOS, Windows, Linux and the web	Operated in Switzerland since 2013 Email, calendars, contacts, files and video calls in one account
Only works with a Proton account Desktop apps need a paid plan after the trial	Hosted service, not something you run yourself Paid service
Downloadable app, Web application, Hosted service	Web application, Hosted service
Closed source	Closed source
License not stated	License not stated
Account needed	Account needed
Not stated if it works offline	Needs internet
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.