The service that connects your product to card networks and banks: it collects card details securely, authorises the charge, and reports the result back to your system.
The gateway decides which countries and methods you can accept, how much each transaction costs, and how many payments silently fail. Changing it later touches checkout, accounting, refunds, and reconciliation at once.
We keep card data out of your servers by using the provider's hosted fields, handle the full lifecycle including refunds, chargebacks, and recurring billing, and reconcile every payment against your records automatically.