A webhook is a mechanism in which one system notifies another via HTTP when a relevant event occurs — the opposite of polling, where one system interrogates another periodically to find out whether there is anything new. Webhooks are push, polling is pull. In practice, webhooks are typically more efficient (communication only when there is something new) and deliver lower latency.
A typical example: a payment system notifies via webhook when a payment is completed — the e-commerce receives the notification and updates the order. Without a webhook, the e-commerce would have to ask the payment system every minute whether the payment was completed — inefficient and slow. Webhooks require the receiving system to have an accessible HTTP endpoint capable of processing the call (security, idempotency, retry on failure).
INFOS products support webhooks for relevant events — new orders in the ERP, stock changes, document receipt, reaching credit limits. Customers configure destination URLs and events to listen for. INFOS implements automatic retry mechanisms to deal with temporary failures in the receiving system, and auditable logs for troubleshooting.