Gathering software requirements using interviews, documents analysis, use cases and workflow analysis. iOS, Android, SpriteKit, Unity, CoreData, UIKit, CoreLocation, Foundation, MapKit, AVFoundation, Grand Central Dispatch, XMPP, network libraries, GPU based image processing, CoreImage, Git, SVN, HTTP, RTMP, HLS, RTMP, HLS, AWS, Wowza, Xamarin, Cordova, Java, Lua, Swift, JS, Objective-C