Building a successful mobile app in a world which welcomes more than 1000 new apps everyday on Google Play Store and Apple Store is not an easy task. Tons of applications are duplicated, useless and sometimes, even if they are performing, the world might not be ready for them yet. However, by offering international calls and various services including Mobile Top Up and early access Remittance at a very competitive price, Rebtel Networks has risen in the last years generating a high revenue and customer satisfaction. Calling has been a profitable business for years, but it might not be the same in the near future, due to the rise in popularity of new free messaging/video calling services such as WhatsApp, Messenger and Skype.