1. Web service integration : Rest/SOAP, JSON/XML, ASIHTTP 2. Persistent Data Storage: Core Data / SQLite / iCloud / File / Plist 3. Image processing: Open CV / Core Image / GPU Image 4. Animation: UIView animation category/ Core animation / Sprite Sheet 5. GPS & Map features: Geo fencing 6. Payment gateway : Apple In App Purchase, Paypal 7. Multiplayer Game server : Apple Game Center, Smartfox 8. Third Party integration : Parse, Urban Airship 9. Messaging platforms: XMPP Chat server, Smartfox, Pubnub 10. Ad Networks : iAd, Chartboost, Applovin, Revmob, Flurry, Admob 11. Mobile Analytics : Flurry, Google, Distimo 12. Cloud integration : iCloud , Dropbox, Google Doc integration 13. Social Network Integration : Facebook, Twitter, LinkedIn, Google+, Youtube, Tumblr, Instagram 14. Notification: Local Notification/ Push notification / Push Notification with parse 15. Game Engine: Cocos 2D/3D, Cocos2dx Sprite-kit, opengl, Sprite S, Unity3D 5.1 , Unreal Engine 4.9, Flash Builder 4.7 16. Physics Engine: Box2d, Chipmunk 17. Google APIs: Custom Search API / Image API / Map and location