- JSON, XML, SOAP - In App Purchase - Push Notification - Facebook APIs, Twitter APIs, LinkedIn APIs - Instagram APIs, Youtube APIs - Google APIs (Map APIs, Place APIs, ... ) - Yelp APIs, Foursquare APIs - DropBox APIs - Bluetooth APIs - Crash Reporting Sevices (Crittercism, bugsense, ...) - Advertisement (iAd, AdMob, RevMob, ... ) - Cocos2D, Cocos3D - Box2D, Chipmunk - OpenGL ES - Corona - Unity3D - Open Faint - Game Center - Artificial Intelligence (Card Game, Chess)