Webhook

A webhook is a mechanism where one application automatically sends an HTTP POST request to a URL in another application the instant a specific event occurs. Instead of the receiving application repeatedly asking "has anything changed?" (polling), the sending application proactively pushes a notification with the event data. In scraping and automation contexts, webhooks are used to receive notifications when an async scraping job completes, when a monitoring alert fires, when a price drops below a threshold, or when a crawl session encounters an error. Webhooks are the backbone of event-driven integration between services.