Mobile Developer
Interview Questions.
15 practice questions across 13 skills — each with what the interviewer is really listening for. Prepare with intent, not guesswork.
Free · No signup · Grouped by skill
How to use this page
Don't memorise answers. For each question, read what the interviewer is looking for, then practise answering out loud in your own words with a real example. The notes describe strong answers and common red flags — they are for your prep, not a script.
Mobile UI Design
2 questionsHow do you manage an app's lifecycle so you do not leak memory or lose state on rotation or backgrounding?
AdvancedWhat the interviewer is looking for: Strong answers explain lifecycle callbacks, saving and restoring state, and releasing resources when backgrounded. Not handling configuration changes or holding references that leak is a red flag.
Your app is smooth on a flagship phone but janky on a budget device. How do you fix it?
AdvancedWhat the interviewer is looking for: Strong answers profile first, reduce main-thread work, optimise lists and images, and test on low-end hardware. Only testing on high-end devices is a red flag.
React Native
1 questionWhen would you choose React Native or Flutter over fully native development?
IntermediateWhat the interviewer is looking for: Look for weighing shared codebase and speed against native performance, platform-specific needs, and team skills. Claiming cross-platform is always better with no trade-offs is a red flag.
Flutter
1 questionIn Flutter, how does the widget tree work and why does setState rebuild efficiently?
AdvancedWhat the interviewer is looking for: A strong answer explains the declarative widget tree, the element/render layers, and that Flutter rebuilds only what changed. Believing the whole UI is redrawn every frame is a red flag.
Swift
1 questionIn Swift, when do you reach for a struct versus a class, and why does value semantics matter?
IntermediateWhat the interviewer is looking for: Look for value types by default for safety and predictability, and reference types when identity or shared mutable state is needed. Defaulting to classes everywhere without reason is a red flag.
Kotlin
1 questionIn Kotlin, how do coroutines help with responsiveness compared to callbacks?
IntermediateWhat the interviewer is looking for: Strong candidates explain structured concurrency, keeping work off the main thread, and readable async code. Doing network or disk work on the UI thread is a red flag.
REST APIs
1 questionHow do you design an app to work gracefully on a flaky mobile network?
IntermediateWhat the interviewer is looking for: Look for caching, offline handling, retries with backoff, and clear loading/error UI. Assuming a fast, always-on connection is a red flag, especially for the Indian market.
App Store Deployment
1 questionHow do you handle app versioning and rollout so a bad release does not hit every user at once?
IntermediateWhat the interviewer is looking for: Look for staged/phased rollouts, monitoring crash rates, and the ability to roll back or feature-flag. Pushing 100% immediately with no monitoring is a red flag.
Mobile Testing
1 questionHow do you write tests for a mobile app given UI and device fragmentation?
IntermediateWhat the interviewer is looking for: Strong candidates layer unit tests, UI tests, and testing on a matrix of devices/OS versions, prioritising critical flows. No automated tests and only manual checks on one device is a red flag.
Git
1 questionHow do you use Git effectively on a team shipping to two app stores?
BasicWhat the interviewer is looking for: Look for a clear branching strategy, PR reviews, and tagging releases per platform. Committing straight to main with no review is a red flag.
Problem-Solving
1 questionHow do you keep sensitive data safe on a device that could be lost or rooted?
AdvancedWhat the interviewer is looking for: Strong answers use secure storage/keychain, avoid storing secrets in plaintext, and minimise on-device sensitive data. Storing tokens or PII in plain preferences is a red flag.
SQLite
1 questionHow do you keep local and remote data in sync so the app works offline and reconciles later?
AdvancedWhat the interviewer is looking for: Strong answers use a local store, a sync strategy, and conflict resolution, with clear UX for pending state. Assuming always-online and no local persistence is a red flag.
TypeScript
1 questionIn TypeScript-based React Native, how do types help you avoid common runtime crashes?
IntermediateWhat the interviewer is looking for: Look for typing navigation params, API responses, and props to catch mismatches early, while validating external data at runtime. Assuming types alone prevent all crashes is a red flag.
Collaboration
1 questionHow do you work with designers to deliver a UI that feels native on each platform?
BasicWhat the interviewer is looking for: Strong candidates respect platform conventions, give feedback on feasibility early, and collaborate on edge cases. Pixel-copying one platform's design onto the other is a red flag.
Behavioural & role-general
1 questionTell me about an app you shipped. What was the hardest platform-specific problem?
BasicWhat the interviewer is looking for: Look for a concrete challenge, how they solved it, and lessons learned. Vague descriptions with no real platform detail suggest limited hands-on shipping.