Avox is a voice and instant messenger application for smartphones with unique features that include free minutes for making domestic and international calls to any cell or fixed number, clear voice calls with no or weak Internet connection using GSM voice channels, peer-to-peer network topology, and advanced chat functions. Avox’s goal is to offer cutting-edge OTT services. The project involves the development of a software solution that will enable its customers to make a specified amount of international and domestic phone calls over GSM networks for a limited amount of free minutes and very low additional charges. The pricing for additional phone calls above the specified freemium limit will be very competitive and will rival much larger companies such as Skype, Viber, Hangouts, and others. Avox overcomes the deficiencies and limitations of VoIP applications, such as Skype and Viber, which constantly require an Internet connection. The software solution is designed to work when 3G or Wi-Fi is weak or not available and enables the user to make free or low cost domestic and international phone calls to either a landline or a mobile phone. This is achieved by Avox proprietary solution that lets users terminate calls from the Internet to the GSM network.