What this operation supports in Google Calendar
Sets up a push notification channel so Google Calendar notifies a webhook when events on a calendar change.
Implementation details
Google's push notifications are a lightweight "something changed" ping -- the actual changed event still needs to be fetched with a separate events list call using a sync token.
Operational considerations
A watch channel expires after a set period and needs to be renewed before it lapses, or change notifications stop arriving silently. Storing the sync token returned from the follow-up events list call is what lets the next poll retrieve only what's changed since, rather than the calendar's entire event history.
Use cases
Google Calendar integration teams rely on this feature to trigger downstream actions when events are created, updated, or deleted in Google Calendar.
- Real-time room-booking or resource changes reflected in automation
- Syncing external systems with calendar event lifecycles in Google Calendar
- Updating dashboards when calendars in Google Calendar change
- Notifying participants via Slack or email when events change in Google Calendar