Google just made the lives of third-party calendar developers much easier. Rather than having to constantly poll Google Calendar servers for updates, the Calendar API now supports push notifications.

Google has made a small change to the Google Calendar API that nonetheless could make a huge difference for developers and users. The Calendar API now supports push notifications - alerts sent ...

This new feature, found in Google Calendar's settings, aims to allow users to prevent third-party apps from viewing their Google Calendar events, even if those apps have general calendar access.