Notes 
#1 
If you decide to self-host EteSync you won't have to pay for the subscription. Tutorial here .
Self-hosted Calendars
The Calendars we recommend, filtered to Self-hosted. See all Calendars →
#2 
End-to-end encrypted sync for calendars, contacts, and tasks, wired into the apps you already use over CalDAV.
#3 
A simple self-hosted CalDAV and CardDAV server for calendars and contacts, written in Python and licensed under GPLv3.
