NimbleCal is built around end-to-end encryption.
What this means
End-to-end encryption means your calendar content is encrypted on your device before it is synced/stored, so NimbleCal cannot read it during normal sync.
Invites are different
When you invite participants to an event, NimbleCal needs to share event details so the recipient can view the invite and RSVP.
Invite details are accessible to anyone with the invite link. Keep invite links private.
See: Invite participants
What might not be encrypted
Some minimal metadata may be stored unencrypted to support features like reminders.
For the detailed, canonical explanation, see: