Wait4Call is an innovative marketing platform through which companies can carry out and manage audio advertising campaigns. The audio spots are broadcasted during any phone call from an Android smartphone while the user is waiting for the response of their interlocutor. The idea behind the app is to optimize the time that is lost when you are on the phone waiting for answer; the user can listen to commercials or promotions based on your preferences, while the company reaches users who are potentially interested in your commercial. Thanks to a personal web platform, the company can quantify the actual number of users reached, decide the target and geolocation by optimizing its marketing campaigns. Finally, in addition to being informed about events or news about products that interest him, the user is rewarded for listening to the commercials and has the choice of whether to cash the credit directly or give it to charity.