An application executed on a first device presents a user interface on a device display. The application is associated with a validation system used by the device. Based on receiving a first user input, the application controls the first device to scan, using a first communication protocol, for other devices that are located within a first communication range of the first device. Based on the scan, the application discovers a second device located within the first communication range of the first device. The application receives, from the second device, an identification information that uniquely identifies a user associated with the second device on the validation system. The application validates the identification information by communicating with a validation server. Based on validating the identification information, the application displays an indication that the second device associated with the user is located within the first communication range of the first device.