A method of determining electric pulses to provide to an unattended machine, the method comprising: at an application executing on a mobile device: detecting, based on a broadcast received from a pulse-providing device that is coupled with the unattended machine, presence of the unattended machine in proximity to the mobile device; after detecting the presence of the unattended machine, receiving, from a server, information about a first set of remotely-configured options for interacting with the unattended machine; in response to receiving the information about the first set of remotely-configured options, displaying, in the application, user interface objects that allow for selection of respective options in the first set of remotely-configured options; detecting a selection of a first user interface object that corresponds to a first option in the first set of remotely-configured options; after detecting the selection of the first user interface object, receiving, from the server, encrypted information that includes an authorization grant for the first option at the unattended machine, wherein the encrypted information includes specifications regarding electric pulses to be provided to the unattended machine by the pulse-providing device in accordance with the first option; in accordance with a determination that a trigger condition has been satisfied, sending the encrypted information that includes the authorization grant and the pulse specifications to the pulse-providing device; and after sending the information that includes the authorization grant and the pulse specifications to the pulse-providing device, receiving a first indication, from the pulse-providing device, that the electric pulses were provided to the unattended machine according to the pulse specifications. detecting, based on a broadcast received from a pulse-providing device that is coupled with the unattended machine, presence of the unattended machine in proximity to the mobile device; after detecting the presence of the unattended machine, receiving, from a server, information about a first set of remotely-configured options for interacting with the unattended machine; in response to receiving the information about the first set of remotely-configured options, displaying, in the application, user interface objects that allow for selection of respective options in the first set of remotely-configured options; detecting a selection of a first user interface object that corresponds to a first option in the first set of remotely-configured options; after detecting the selection of the first user interface object, receiving, from the server, encrypted information that includes an authorization grant for the first option at the unattended machine, wherein the encrypted information includes specifications regarding electric pulses to be provided to the unattended machine by the pulse-providing device in accordance with the first option; in accordance with a determination that a trigger condition has been satisfied, sending the encrypted information that includes the authorization grant and the pulse specifications to the pulse-providing device; and after sending the information that includes the authorization grant and the pulse specifications to the pulse-providing device, receiving a first indication, from the pulse-providing device, that the electric pulses were provided to the unattended machine according to the pulse specifications.