Flutter Interview Questions: Beginner to Advanced

🟢 Beginner

1. What is the difference between Stateless and Stateful Widgets?
2. What is the difference between final and const?
3. What is the difference between runtime constant and compile-time constant?
4. What does main() do vs runApp()?
5. What is context in Flutter?
6. What are null-aware operators in Dart?
7. What is assert() and when is it active?
8. What is async/await and how does asynchronous programming work in Dart?
9. What is the difference between a Future and a Stream?
10. What is the difference between EQUAL (=) and LIKE in a SQL query?
11. What are the different build modes in Flutter (Debug / Profile / Release)?
12. What does flutter run --verbose do?
13. What are Class Constructors in Dart? What types exist?
14. What is a typedef in Dart?
15. What is the difference between Expanded and Flexible?

🟡 Intermediate

16. What is the late keyword and when should you use it?
17. What are extension methods and when would you use them?
18. What are mixins and when should you use them?
19. What are Keys in Flutter? (ValueKey, ObjectKey, UniqueKey, GlobalKey)
20. What is InheritedWidget and how does it work?
21. What is setState() and how does it relate to markNeedsBuild()?
22. What is the Widget lifecycle in a StatefulWidget?
23. What are the three trees in Flutter? (Widget → Element → Render)
24. What is the difference between Slivers and regular Widgets?
25. What are Intrinsic Widgets and when should you use them?
26. What is a Singleton and why would you use one?
27. What is Dependency Injection (DI) and why is it useful?
28. What is the difference between abstract, interface, and sealed classes? When do you use each?
29. What is the difference between Bloc, Provider, and Riverpod?
30. What are Freezed and Equatable packages? What is value vs reference equality?
31. What is Tree Shaking and why does it matter?
32. Why split-per-ABI when building an Android APK?
33. What is MVVM vs MVC architecture?
34. What are SOLID principles and how do they apply to Flutter?
35. Functional vs class-based Widgets — which is recommended and why?

🔴 Advanced

36. What is JIT vs AOT compilation in Dart?
37. How does the Dart Event Loop work? (Microtask queue vs Event queue)
38. What are Isolates? How do they work and how do they communicate?
39. What are Platform Channels, Method Channels, and Event Channels? How do you use them to integrate native code?
40. What is Clean Code Architecture and how would you structure a Flutter app with it?
41. What is get_it and how do you use it for Dependency Injection?
42. What is Socket management and how do you handle it with AppLifecycleListener?
43. What is FFI (Foreign Function Interface) and why is it used?
44. What are iOS Keychain and Android Keystore? How do you handle secure storage in Flutter?
45. What are the different types of testing in Flutter? (Unit / Widget / Integration / Coverage)
46. What is CI/CD and how would you set it up for a Flutter project?
47. What is InheritedWidget under the hood and how do Provider/Riverpod build on top of it?
48. Tell me about the best project you’ve done so far. Why do you think it’s the best?

Final Thoughts

Flutter interviews span a wide surface area — from low-level rendering internals to architecture patterns to platform-specific security. The candidates who stand out aren’t those who memorize answers, but those who can explain why something works the way it does and discuss the trade-offs thoughtfully.

Good luck.

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