After the buy button is clicked, the merchant’s payment gateway collects the   transaction and order information and passes it to the merchant’s payment processor. The merchant’s payment processor is then routed to the customer’s issuing bank via   the card association network, who informs the payment processor which issuing bank   the customer belongs to. The merchant’s payment processor will then check with the customer’s issuing bank to see if the card passed to it: is valid, has the funds available for purchase, and if the transaction passed the AVV/CVS check. The issuing bank will then indicate to the payment processor if the card information   passed to it was accurate or not and if the payment is possible. If the issuing bank confirms that the card used in the transaction is available, the   payment processor will either put: an authorization hold on the funds, or, will do a capture on the funds and immediately transfer the money to the merchant’s   acquiring bank, where the funds will settle in the merchant account. https://www.signifyd.com/resources/fraud-101/how-online-payments-work/