Split (the “app”) is designed to split payments between friends. The app is designed to hold balances between friends by recording charges and payments between them. The split algorithm is designed for groups and group activities in which multiple users are involved in spending and paying the bills. This report outlines the derivation and implementation of the split algorithm as well as the development of the full stack application’s relational data model, RESTful backend server and cross-platform (iOS/Android) mobile app. The project also explores the implementation of in-app payments and how to leverage existing financial systems to allow users to make peer to peer payments to offset their balances with their friends in the context of Split.