Described are a system, method, and computer program product for customizing functions of a point-of-sale (POS) terminal. The method includes receiving payment device data from an electronic payment device of a user during a payment transaction between the user and a merchant. The method also includes receiving at least one script for execution on the POS terminal from the electronic payment device. The at least one script is associated with a digital signature. The method further includes verifying the at least one script based on the digital signature of the at least one script and executing the at least one script on the POS terminal to cause an action associated with a user interaction with the POS terminal to be performed.