iOS Developer Interview
Questions & Answers

Swift uses Automatic Reference Counting (ARC) — you do not manually allocate/free memory, but you must avoid retain cycles. Use weak or unowned references in closures and delegates where a strong reference would create a cycle. Instruments' Leaks and Memory Graph tools identify retain cycles. Common culprits: delegate properties (should be weak), closures capturing self strongly, and NotificationCenter observers not removed on deinit.

Core Data or SQLite for local persistence. Queue network requests when offline and sync when connectivity returns — use a background URLSession and retry logic. Conflict resolution strategy for when local and server data diverge. NSNetworkReachability or Network framework to observe connectivity changes. Show you have thought about the user experience during the offline state — clear messaging, cached data, and graceful degradation.

Profile with Instruments before optimising — Time Profiler for CPU, Allocations for memory, Core Animation for rendering. Main thread rule: no network requests, disk I/O, or heavy computation on the main thread. Reduce view hierarchy depth for smoother scrolling. Use lazy loading for images (SDWebImage or async/await + URLSession). Battery impact matters: minimise background refresh, batch location updates, and use significant-location-change API instead of continuous GPS where possible.

Know the most common rejection reasons: guideline 4.2 (minimum functionality), 2.1 (metadata spam), 3.1.1 (in-app purchase bypass), and privacy policy missing for data-collecting apps. Write clear metadata and review notes that explain non-obvious features. For rejections: read the specific guideline cited, fix the issue fully before resubmitting, and use the Resolution Centre to ask clarifying questions if the rejection is ambiguous.

Auto Layout with adaptive constraints rather than hardcoded frames — always. Size classes for major layout differences (compact vs regular width). Test on the two oldest supported iOS versions and the latest. SwiftUI's automatic safe area handling vs UIKit's explicit safe area insets — know both. Feature-flag or guard with #available for APIs only available on newer iOS versions.

Structure your answer as a 60-second professional narrative: where you have been (your background), what you have done (your strongest achievement), and where you are going (why this role). Lead with your most relevant experience, not your entire career history. End with why you are excited about this specific opportunity.

Choose a genuine weakness that you have actively worked to improve. The structure is: name the weakness → show self-awareness of its impact → describe the concrete step you took to address it → show the improvement. Never say "I work too hard" — interviewers recognise this as evasion and it damages your credibility.

Use the STAR method (Situation, Task, Action, Result) but add a fifth element: what you learned. Choose a real failure, not a disguised success. Show you can take responsibility without making excuses, and demonstrate that the lesson changed your behaviour in a specific, verifiable way.

Be honest but constructive. Acceptable reasons: seeking greater scope, new challenge, skills you can not develop in the current role, or company-level changes (restructuring, direction shift). Never speak negatively about your current employer or manager — it signals you will do the same to the prospective employer in future conversations.

Describe the conflict specifically, show that you sought to understand the other person's perspective, and explain the resolution approach you took. Interviewers are assessing your emotional intelligence and whether you escalate or resolve. Avoid stories where you were right and they were wrong — choose a story where both parties grew.

Describe your specific prioritisation system: impact × urgency matrix, stakeholder alignment, or a specific tool or process you use. Then give an example where you applied it under real pressure. Show that your system is systematic rather than reactive, and that you communicate proactively when priorities change.

Choose an achievement that is specific, measurable, and relevant to the role. Lead with the result ("I reduced our error rate by 40% in 90 days"), then explain the context, challenge, and what you specifically did that drove the result. Show your ownership and impact, not just your team's work.

Be honest about your ambitions while showing that this role is a genuine step in that direction — not a stopgap. Hiring managers want to invest in people who will grow with the organisation. Show that your 5-year goal requires the specific skills and experience this role provides, making your ambition an asset for both sides.

Research before the interview and make the answer specific: cite their product, a recent company development, something about their culture or team, or a professional aspect of this particular role that matches your goals. Generic answers ("I love your values") signal you did not do the research. Specific answers signal genuine interest.

Always have 3–5 questions prepared. Ask about the biggest challenge in this role, what success looks like in the first 90 days, how the team operates, and the interviewer's own experience at the company. Never ask about salary, benefits, or holidays in a first interview. Questions show interest, strategic thinking, and that you care enough to have done research.