A smartphone (106) with a processor (150) can execute program instructions to cause currency transfers transactions to be made to accounts associated with other smartphones and to interact with an application server (102) or merchant terminal (108). The smartphone can scan a quick response (QR) code and decode the QR code to recover encoded data. The smartphone can use the encoded data, alone or with other data, such as data from a user profile, to obtain promotional vouchers from the merchant server. The smart phone can initiate redemption of the promotional vouchers. The smartphone can display a validation form to prompt capturing images of items an application server can use to validate payment instruments and accounts. The validation form may prompt a user to capture images of a driver's license, a payment instrument, an invoice, or a passport. Smartphone communication with the application server can include device identifier such as MSISDN, IMEI, or IMSI.