A secure point-of-sale (POS) portal architecture for delivering multiple services is provided. According to one exemplary aspect of the architecture, a number of services offered by various parties are integrated for delivery to merchants. The parties offering the services include, for example, payment processors and merchant acquirers and other external value-added service providers. The integrated services, in turn, are offered to merchants and/or their respective customers via one or more POS devices and its supporting system infrastructure at the merchant locations. The integrated services include, for example, acceptance of multiple payment instruments, payment processing, user dialog management, sales promotion and customer support, loyalty programs, back office processing, receipt capture, employee training, risk management, dispute resolution, system security, system administration etc. Moreover, these integrated services may be customized based on a merchant's particular requirements to provide a specific environment for delivering these services.