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Your candidate aced the LeetCode algorithm problem. But can they handle offline sync? Do they understand how to optimize app startup time? Have they ever dealt with an App Store rejection? LeetCode doesn't test mobile development skills. Here are questions that do.
Mobile-Specific Technical Questions
Look for understanding of local storage (SQLite, Realm, Core Data), conflict resolution strategies, background sync, and user experience during poor connectivity.
Crash reporting tools (Firebase Crashlytics, Sentry), symbolication, looking for common patterns (OS version, device model), and reproducing with simulators or test devices.
Strong candidates know the steps: certificates, provisioning profiles, App Store Connect setup, TestFlight, review guidelines, and common rejection reasons (privacy, performance, guidelines).
Real-World Problem Solving
Local database with timestamps, message queue for pending sends, optimistic UI updates, and conflict resolution based on server timestamps.
Lazy loading, background initialization, optimizing first paint, reducing bundle size, using splash screens effectively, and measuring with performance tools.
How to Evaluate Answers
Strong candidates usually:
- ✦ Provide examples from production systems
- ✦ Discuss trade-offs instead of absolute solutions
- ✦ Mention monitoring and observability
- ✦ Explain failure scenarios and recovery plans
- ✦ Reference mobile-specific constraints
- ✦ Demonstrate user-experience awareness
What to Look for in a Portfolio
A strong mobile portfolio includes:
- ✦ Apps in the App Store or Google Play (not just GitHub repos)
- ✦ Screenshots of edge cases (offline mode, error states, loading states)
- ✦ Evidence of handling real-world constraints (API flakiness, poor connectivity)
- ✦ User reviews and ratings (positive is good, but how they handled negative is informative)
Red Flags in Interviews
Walk away if they:
- ✦ Can't name a previous app they shipped
- ✦ Don't understand mobile-specific constraints (battery, memory, network)
- ✦ Have never dealt with an App Store rejection
- ✦ Can't explain how to handle push notifications
- ✦ No experience with crash reporting or analytics
Questions for References
Ask previous managers or clients:
- ✦ Did the developer deliver on schedule?
- ✦ How did they handle production incidents?
- ✦ Were they proactive in identifying risks?
- ✦ How strong was their communication?
- ✦ Would you hire them again?
- ✦ What type of projects suited them best?
Test Real Mobile Skills
Stop using generic coding interviews for mobile roles. Test what actually matters. Offline Pixel pre-vets app developers on these exact skills. Raise a request, talk to candidates, fund the project, and approve payment when you're satisfied.
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