Buttondown Documentation
Events are Buttondown's way of telling you that something interesting has happened to your newsletter, and webhooks are Buttondown's way of letting you react to various incoming events. For example, when a new subscriber signs up for your newsletter, Buttondown creates and emits a subscriber.created event; when that subscriber unsubscribes, Buttondown creates a subscriber.unsubscribed event. If you wanted to, say, create a Slack notification or run some application code whenever something in Buttondown happens, you'd create a webhook for the concomitant event and point it towards your application.
The payload of most events are fairly simple, and look something like this: