Tendigi is a web design agency that has closely monitored the evolution of the iPhone. For years, this company has adapted to the technology that defines this popular Apple smartphone. The programmers at Tendigi have mastered their skills in the Swift programming language that is compatible only with iOS and other operating systems that are licensed by Apple. Swift is usually combined with Objective-C in powerful suites such as Apache Cordova. This is a sophisticated program that was once known as PhoneGap. Google Firebase is another tool that gives developers convenient ways to write code for iPhone apps. Tendigi is also familiar with the Cocoa Touch technology that controls the behavior of apps on touch screens. When a person taps the screen on an iPhone, this framework executes multiple commands on the back end. The Cocoa Touch interface essentially links a person's physical input to the virtual elements of an app.