A merchant uses a merchant point of sale (POS) device to identify items or services for purchase by a customer, and costs for each. One or more payment amounts are sent from the merchant POS device to a checkout server using an application programming interface (API), which the checkout server sends on to an authorized payment terminal device that then reads payment information from a payment object and sends the payment information back to the checkout server. The checkout server processes the transaction and confirms transaction completion to the merchant POS device and payment terminal device.