A mobile device is used to initiate and execute a transaction between a customer and a merchant. A mobile device is used to initiate a point of sale transaction, wherein a merchant ID is sent to a payment processing server. Responsive to receiving a communication from the mobile device, the payment processing server requests transaction information from the merchant, wherein the merchant is identified based on the provided merchant ID. The merchant can provide transaction information such as the total sale amount to the payment processing server. The payment processing server can authenticate the customer and initiate a purchase transaction with the appropriate financial institutions associated with the customer and the merchant. The payment processing server can send a confirmation of the executed transaction to the merchant and the mobile device.