Push notifications are great alerts for Recurly changes. Whenever an account is modified your push notification listener will be notified and a quick API query can be used to verify the contents of a push notification for action. Many Recurly merchants use push notifications to de-provision accounts with declined payments, track daily signups, or alert their account management teams to customer cancellations.
The folks over at Pipedrive have gone one step further with their push notification integration. In just one afternoon, they used push notifications to create a performance monitor. Now their team is able to see (and hear!) transactions as they occur.