JoinPay is a location-based mobile payment app that aims to facilitate P2P (peer-to-peer) payments. It covers the basic P2P payment functions that allow money to be sent to or requested from users in their contact lists. In addition, it automatically displays nearby friends and others who have their JoinPay apps opened in the foreground. In this way, users can simply tap the targets to start a transaction without manually typing their account information or searching for them in the contact list. Moreover, money can be divided intelligently allowing the amount of each target to be adjusted in accord with users’ need.