App development consists of UI UX design, front end development, back end development, app hosting service and regular bug fix maintenance. UI (user interface) designs the features and display which a person interacts with, user-friendliness layout and aesthetics have to be consider in UI design. UX design (user experience) are done according to user's behaviour and patterns to allocate the design characteristics, enhancing user satisfaction. For instance, what kind of content to put first for user's convience. Back end devleopment stores data, encryption, account management, sending notifications/messages, social media integration...