A webhook (also called a web callback or HTTP push API) is a way for an app to provide other applications with real-time information. A webhook delivers data to other applications as it happens, meaning you get data immediately.
For Hio specifically, a webhook is used to connect us with Eventbrite on your behalf. This allows us to send emails to attendees who register on Eventbrite automatically about attending your event on Hio. We do this to free up more time for you to focus on other things, knowing that Hio's got your back in the communication department!