I'm Oanh, Marketing Lead at Pion, a small tech team (under 20 people) based in Vietnam. We build software for individuals and online businesses, from fintech and payment tools to cloud services.
A webhook is an HTTP callback. When an event happens in system A, system A proactively sends an HTTP request (usually a POST) to a URL you provided, carrying data about that event.
In short: instead of you asking over and over, the other system tells you when something happens.
Real-life analogy: You order something online. Polling = walking to the front door every 10 minutes to check if the courier has arrived. Webhook = leaving your phone number so the courier calls you when they're outside.
