Which API you will be using? Any custom build or any other?
Area of my expertise includes:
Native IOS, Objective-C; Swift; OOP, MVC, main design patterns, DB engineering; Apple's Xcode IDE Frameworks and APIs like Foundation, UIKit, and CocoaTouch; iOS 10 and newer OS versions. A Git code repository technology.
Android SDK; OOPS; XML; JSON;
Java (UI, working with database, Java Applets, multithreading, client-server interaction via TCP/IP), ASM
Html5, Bootstrap, CSS3, Ajax, XML, JSON, JQuery, WebAPI
Please ping me to discuss further.