The short answer
Choose Flutter if you need iOS and Android on day one from one budget and one team, and your interface is your own design rather than the platform’s. Choose Swift if most of your users are on iPhone, the app should feel like an iPhone app, or it depends on iOS features such as widgets, Live Activities, Siri or Apple’s on-device AI.
The one difference that explains the rest
A Swift app uses Apple’s own controls: the same navigation bars, lists, sheets and text fields as the rest of iOS. Flutter draws its own interface with its rendering engine, Impeller, which the Flutter team describes as the only supported renderer on iOS (Flutter docs). Flutter’s Cupertino widgets imitate iOS controls closely, but they are reproductions, so they change when Flutter updates them rather than when Apple does.
That matters more each year. On iPhone Duo, for example, Apple says apps built from standard system components get the new vertical toolbars and tab bars automatically (Apple). An interface drawn by a framework gets them when the framework adds them.
Side by side
| Swift and SwiftUI | Flutter | |
|---|---|---|
| Language | Swift | Dart |
| Interface | Apple’s system controls | Drawn by Flutter, with iOS-style widgets |
| New iOS features | Available the day iOS ships | When Flutter or a plugin supports them |
| Widgets and Live Activities | Built in SwiftUI | Need a native extension written in Swift |
| Accessibility | VoiceOver and Dynamic Type built into the controls | Supported, through Flutter’s own layer |
| Android from one codebase | No | Yes |
| Best when | iPhone-first, native feel, deep iOS features | Two platforms, one team, a custom look |
When Flutter is the better choice
- You need Android and iOS on day one and can only fund one team.
- Your interface is entirely your own and is meant to look identical on both platforms.
- Your team already writes Dart, or your web team will share the work.
- The app is mostly forms and content, with little that depends on new iOS features.
In those cases Flutter can cost less up front, and we will say so on the first call.
When Swift is the better choice
- Most paying users are on iPhone, so the iOS version is the one that has to be best.
- The app should feel like iOS: scrolling, gestures, the keyboard and navigation behaving exactly as people expect.
- It depends on Apple features: widgets, Live Activities, App Intents for Siri, the Foundation Models framework, HealthKit or Apple Pay.
- It will be maintained for years, through Apple’s yearly changes in design and APIs.
Apple published a story about Swiggy, which moved two parts of its app from a hybrid setup to Swift and SwiftUI from early 2024. The team reported faster load times, smoother scrolling and more fluid animations, most noticeably on older devices.
Is Flutter cheaper?
For two platforms built at once, often yes. For an iPhone app on its own, rarely: you pay for the framework layer without using its main benefit. And the saving shrinks if you need native extensions, platform-specific design, or fixes when iOS changes something the framework has not caught up with. See what an iOS app costs.
Already on Flutter?
You can move the iOS app to Swift and keep everything that matters: the same App Store listing, the same subscribers and the same backend. Your Android app can stay on Flutter. See moving to native Swift, and our longer argument in why we only build in Swift.
Related: Why we only build in Swift · Kotlin Multiplatform vs Swift · React Native and Flutter to Swift