Flutter FAQ: Performance, Hot Reload, Platform Support, and More

Flutter is a free open‑source SDK that enables developers to build high‑performance native‑like applications for Android and iOS from a single codebase.

Question 1: What performance can a Flutter app achieve? Flutter targets 60 fps stable frame rates, runs compiled native code, and launches quickly because there is no interpretation step.

Question 2: How long is the development cycle when using Flutter? Flutter uses hot‑reload, allowing sub‑second code‑to‑screen updates on devices or emulators, and the state is preserved across reloads.

Question 3: What is the difference between hot‑reload and hot‑restart? Hot‑reload injects changed Dart code into the running VM, preserving app state; hot‑restart restarts the application from main(), losing state. Certain changes (global variable initializers, static field initializers, main()) cannot be hot‑reloaded.

Question 4: Where can a Flutter app be deployed? It can be compiled and deployed to iOS and Android platforms.

Question 5: Which devices and OS versions does Flutter support? Android Jelly Bean (API 16) or newer, iOS 8 or newer, iPhone 4S or newer, and ARM Android devices. x86 Android builds are not directly supported but work via ARM emulation.

Question 6: Does Flutter run on the Web? Flutter Web is currently in technical preview; developers can package existing Flutter code for the web, but it may show warnings.

Question 7: Can Flutter be used to build desktop applications? Desktop support exists but is still maturing; progress is tracked on the Flutter wiki.

Question 8: Can Flutter be embedded into an existing native app? Yes, Flutter views can be embedded in Android or iOS apps, though tooling is not yet fully optimized for this scenario.

Question 9: Can Flutter access platform services such as sensors or local storage? Flutter provides APIs for many platform services, and additional functionality is available through packages on pub.dev or via platform channels.

Question 10: Can built‑in widgets be extended or customized? Flutter’s widget system encourages composition; developers can combine smaller widgets to create custom UI components, such as building a button from Material and GestureDetector widgets.