Glossary
Calendar Sync Glossary
Plain-English definitions for the terms that come up when you sync calendars across platforms.
- CalDAV
- CalDAV is the open standard for reading and writing calendar events over HTTP. It is what lets Apple Calendar, Fastmail, Yahoo Calendar, and self-hosted servers like Nextcloud expose events to third-party clients.
- ICS (iCalendar)
- ICS is the standard text-based file format for calendar events. Subscribing to an .ics URL is a read-only way to pull events into a calendar app.
- OAuth for Calendars
- OAuth 2.0 is the standard that lets you grant a third-party app limited access to your calendar without sharing your password. Google and Microsoft both use it for calendar APIs.
- Two-Way Sync
- Two-way (bidirectional) sync mirrors changes in both directions. An event created or edited on either calendar is reflected on the other within minutes.
- Webhook
- A webhook is an HTTP callback that a service sends when something changes. Google and Microsoft use webhooks to notify SyncCal the moment a calendar event is created, updated, or deleted.