what is payment gateway?

Payment gateways are a service that helps merchants initiate ecommerce, in-app, and point of sale payments for a broad variety of payment methods. The gateway is not directly involved in the money flow; typically it is a web server to which a merchant's website or POS system is connected. A payment gateway often connects several acquiring banks and payment methods under one system.

processor of the authorization reply to the payment gateway.

Popular payment gateways include PayPal/Braintree,Sepordeh, Stripe, and Square.

That’s why it’s important to understand that the quality of your ecommerce payment gateways helps you fend off these attacks in real-time, providing a buffer of encryption between buyer and seller.