ProtonCalendar uses end-to-end encryption to keep your data private, with no third parties including ProtonMail able to see your events. It has the standard calendar features you would expect, such as the ability to create and delete events, to set reminders and to have events repeat daily, weekly or monthly.
The calendar is available online, but the company says it’ll launch dedicated iOS and Android apps next year. The web version is currently in beta mode, but it will be available to all users, including free users, once it leaves beta.
ProtonMail says it is also working on a secure cloud file storage service called ProtonDrive, coming soon. For now, paid ProtonMail users can access the calendar by logging in to the Beta site.