The RavenDB client offers a push notification feature that allows you to receive messages from a server about events that occurred there.
You are able to subscribe to events for all documents, indexes, and operations as well as to indicate a particular one that you are interested in.
This mechanism lets you notify users if something has changed without the need to do any expensive polling.
Accessing Changes API
The changes subscription is accessible by a document store through its IDatabaseChanges interface.