Proton Calendar

Proton Calendar is a calendar service from the Swiss company Proton with a strong focus on privacy. It uses zero-knowledge encryption, which means the company cannot read the contents of your calendar even though the entries are stored on its servers.

The service is hosted in Switzerland and falls under Swiss privacy law, which makes it a European alternative to the calendars bundled with American office suites. It fits people already using other Proton products and anyone who treats their schedule as sensitive information.