A system and an arrangement that process payment requests received from a number of distinct data communication devices via respective communications channels and consistent with different communications protocols. In an example embodiment, a payment processing system includes a plurality of data communications devices that transmit a plurality of payment requests in connection with purchases via respective communication channels. Each transmitted payment request includes a merchant identification code and a set of customer financial account data. The system further includes a payment server arrangement that receives the payment requests from the data communications devices at the respective channels via a plurality of adapter modules corresponding to each of the communication channels. Each of the adapter modules includes a payment processing application that identifies a financial institution identification code associated with the merchant identification code. The adapter modules interface with a data processing system of the financial institution consistent with a communications protocol associated with the identified financial institution.