An application executing on a mobile computing device retrieves encoded information from a physical package by invoking a scanning function of the mobile computing device. The encoded information associates the physical package with a transaction. The mobile computing device transmits, using the encoded information, an item of recipient reaction information to a server at a network location. The mobile computing device receives from the server an item of transaction information associated with the transaction. The item of transaction information is usable by the application to perform a user interaction function related to the transaction. The mobile computing device performs the user interaction function.