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Mobile App Developer interview questions

Mobile interviews test how well you understand the app lifecycle, state management, performance on low-end devices and the release process. Interviewers love candidates with an app on the Play Store or App Store they can demo.

11 questions with answer notes · 4 rounds · By the JOBSPOT 360 team

How the selection process usually works

  1. 1

    Online assessment

    DSA problems and MCQs on Dart, Kotlin or Swift.

  2. 2

    Platform fundamentals

    Lifecycle, widgets or views, navigation, state management and async programming.

  3. 3

    Machine coding

    Build a small screen, such as a list that loads from an API with search, pagination and error handling.

  4. 4

    Project and HR

    Walkthrough of an app you shipped, then HR.

Rounds vary between companies. Smaller teams often merge the technical and managerial rounds, while larger companies may add an extra technical round.

Skills to brush up on

  • Flutter and Dart, Kotlin, or Swift
  • State management (Provider, Riverpod, BLoC, ViewModel or SwiftUI state)
  • REST APIs and JSON parsing
  • Local storage (SQLite, Hive, Room or Core Data)
  • Firebase (auth, push notifications, Crashlytics)
  • App lifecycle
  • Play Store and App Store release process
  • Git

Technical questions

  1. 01 Flutter: what is the difference between a StatelessWidget and a StatefulWidget?

    How to answer: Stateless widgets depend only on their configuration; stateful widgets hold mutable state in a State object and rebuild when setState is called.

  2. 02 Flutter: explain the widget, element and render object trees.

    How to answer: Widgets are cheap, immutable configuration. Elements hold the place in the tree and manage lifecycle. Render objects do layout and painting.

  3. 03 Android: describe the Activity lifecycle and what happens on screen rotation.

    How to answer: onCreate, onStart, onResume, onPause, onStop, onDestroy. Rotation recreates the activity by default, so keep state in a ViewModel or saved instance state.

  4. 04 iOS: what is the difference between struct and class in Swift, and what are retain cycles?

    How to answer: Structs are value types; classes are reference types managed by ARC. Retain cycles happen when two objects hold strong references to each other. Break them with weak or unowned.

  5. 05 Which state management approach do you use and why?

    How to answer: Name one you have used in production, explain how it separates UI from business logic, and when you would choose something simpler.

  6. 06 How do you handle async work like API calls without freezing the UI?

    How to answer: Use async/await (Dart and Swift) or coroutines (Kotlin) and keep heavy work off the main thread. Show loading and error states.

  7. 07 How do you store data offline and sync it when the network returns?

    How to answer: Persist locally, mark unsynced records, queue changes and retry with backoff. Mention how you resolve conflicts.

  8. 08 How do you reduce app size and improve startup time?

    How to answer: Compress assets, remove unused packages, use deferred loading and lazy initialisation, and profile with DevTools, Android Profiler or Instruments.

Scenario questions

  1. 01 Build a screen that lists products from an API with pull-to-refresh and infinite scroll.

    How to answer: Separate the API layer, state and UI. Handle loading, empty, error and end-of-list states, and avoid duplicate page requests.

  2. 02 Your app crashes only on some Android devices. How do you investigate?

    How to answer: Check Crashlytics for device, OS version and stack trace, reproduce on an emulator with the same API level, and look for permission or memory issues.

  3. 03 How do you release an update without breaking users on older versions?

    How to answer: Keep the API backward compatible, use staged rollouts, feature flags and a forced-update check for breaking changes.
Then comes the HR round Almost every interview ends with HR questions about you, your plans and your salary expectations. See the common ones and how to answer them.

Resume tips for this role

  • Link your published apps with download counts or ratings if they are respectable.
  • Mention the state management, architecture and backend services you used for each app.
  • Add screenshots or a short screen recording to your GitHub README.
  • Note performance or stability improvements, such as crash-free sessions going from 97% to 99.5%.

This guide is written by the JOBSPOT 360 team from common interview patterns for this kind of role. It is not provided by any employer, and real interviews will differ. Read our editorial policy.