There is a way to stream feature flag and configuration changes to the clients right when they happen. In some cases ConfigCat's pull based architecture does not completely satisfies the requirements when microservices need the latest values instantly, or mobile apps where polling sometimes is a battery consuming anti-pattern.
Your application subscribes to a PubNub channel to get updates about changes. And useConfigCat Webhooks to notify PubNub when a feature flag value gets updated.Sample application in Node.js.![push-noti](/assets/push-noti.png)