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
- Hosting
- 🇨🇭 Switzerland, 🇩🇪 Germany, 🇳🇴 Norway
- Company
- Proton AG
- Founded
- 2019
- Ownership
- Non-profit
- Infrastructure
- Own infrastructure
- Open source
- Full
- GDPR
- Compliant
- Pricing
- Freemium · from Free
- Free tier
- Yes
- Platforms
- Web, Ios, Android
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
Pricing & availability
Pricing modelFreemium
Starting priceFree
Free tierYes
PlatformsWebiOSAndroid
Languages
ENFRDEESITNLPTPL
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.