Proton Calendar
Swiss end-to-end encrypted calendar by Proton AG. All event details (titles, descriptions, locations, attendees) are encrypted so even Proton cannot read them. ISO 27001 certified, independently audited annually by Securitum, own infrastructure in Switzerland and Germany.
Quick facts
Headquarters Geneva, Switzerland
Company Proton AG
Founded 2019
Ownership Non-profit
Hosting 🇨🇭 Switzerland, 🇩🇪 Germany, 🇳🇴 Norway
Infrastructure Own infrastructure
Data jurisdiction EFTA
Open source Full
GDPR Compliant
Pricing Freemium · from Free
Free tier Yes
Platforms Web, iOS, Android
Languages
ENFRDEESITNLPTPL
95 · Certified European
Try for free Why does it score 95?
Legal jurisdiction
EFTA country HQ
25/30Ownership & control
Non-profit ownership
25/25Data sovereignty
Own infrastructure
30/30Accountability & trust
Fully open source + GDPR + audited
15/15EuroPoints total
95/100
See how they compare
Proton Calendar
Tuta CalendarEuroPoints
Certified European
Certified European
Legal jurisdiction
Ownership & control
Data sovereignty
Accountability & trust
Independence bonus
Headquarters
Geneva, Switzerland
Hanover, Germany
Founded
2019
2024
—
Open source
Full
Full
—
Infrastructure
Own infrastructure
Own infrastructure
—
GDPR
Free tier
Pricing
Freemium · from Free
Freemium · from Free
—
Platforms
Web, iOS, Android
Web, iOS, Android, Desktop
—
Languages
en, fr, de, es, it, nl, pt, pl
en, de, fr, es, it, nl, pt, pl
—
What does it replace?
Google Calendar 
Apple Calendar 
Outlook More European Calendar & contacts alternatives
#1
Tuta Calendar
100 · Certified EuropeanGerman end-to-end encrypted calendar by Tutao GmbH, tightly integrated with Tuta Mail. All calendar data is encrypted on German servers using post-quantum TutaCrypt encryption. Standalone calendar app launched in 2024. Open source, no ads, no tracking.