Abstract: The present document describes a payment system that processes transactions originating from mobile phones, cellular devices, Web browsers, or other mobile devices. A customer initiates a transaction by sending a payment request via SMS, HTTPS, or other network protocol. The payment request includes an amount to be paid and a phone number associated with a recipient. The payment system confirms the identity of the customer, and identifies the recipient based at least in part on the phone number. The payment system supports the fulfillment of payment requests with various combinations of account balances, credit accounts, discounts, and loyalty points. The payment system also provides various merchant features such as ticket vending, automatic discovery of payees and payers, management of merchant terminals, and payroll processing.