Your coding should be standard and can be validated by App store. You should avoid the code from any opensource because license agreement for opensource prohibits you to use in proprietary platform like Apple as agreement state that your code should be open to use for others and that is not possible for iPhone app programming. Another thing likely avoid is Flash as iPhone doesn’t support the Flash components at all. Design and usability aspects should exert excellent user experience because low quality app means no selling and no income for App store.
During iPhone app programming you should conduct frequent testing so you can eliminate bugs at all because App store won’t approve apps with bug. As far as performance is concern simulator may be differ from real device so it is better you test on real device. These all standards kept by all reputed outsourcing iPhone app programming companies so you just need to get assurance of their support up to approval of your app in App store.
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