Swift

Swift is Apple’s programming language for a native app on iPhone, iPad, and Mac. The code speaks iOS directly, so camera, location, and background work can use the platform’s own hooks. You maintain Apple’s tools, updates, and app store review on purpose.

Kotlin is the close pair: the language Google recommends for Android. Swift does not build that Android app. A cross-platform product, often React Native or Flutter, shares one codebase and skips writing most of the product in Swift.

A real-life example of Swift

A Midtown photographer wants the iPhone app to pull a shoot’s photos from the camera roll into a client gallery, with the same gestures as the rest of iOS. Kotlin cannot ship that iPhone build. A shared codebase can cover the gallery on both phones; Swift is the bet when the camera roll has to feel like Apple’s own.

Write Swift when the iPhone itself is the feature. Read native, cross-platform, or web and Swift and Kotlin for native apps.