Which situation illustrates the use of a webhook application?
- A user sends a REST API call to a webhook server to poll a predefined data set.
- Triggered by the operation of a user, a mobile application sends a REST API request to get information from a webhook server.
- A network automation application queries a router to get CPU and memory usage over a period of time.
- A developer subscribes to a webhook server for an application so that the application will receive a notification when an event occurs.
Explanation: A webhook is an HTTP callback, or an HTTP POST, to a specified URL that notifies a registered application when an activity or event has occurred in one of the resources on the platform. Webhooks enable applications to get real-time data. With webhooks, applications are more efficient because they no longer need to have a polling mechanism.