What is a merchant payment gateway?

A payment gateway is a software application that acts as a conduit between an eCommerce merchant’s website and the bank that will authorize (or decline) a customer’s credit card payment.

Regardless of the payment method used, the primary function of the payment gateway is to securely transmit sensitive credit/debit card or bank account information from the customer to the customer’s issuing bank and all other parties that are involved in the transaction.