iOS Developer interview questions & mock practice
What interview questions are asked for a iOS Developer?
A iOS Developer interview in 2026 runs across 4 rounds — swift fundamentals, uikit / swiftui round, memory & concurrency, coding + design. Below are the most-asked iOS Developer interview questions and a focused prep plan. Rehearse every answer with OnJob's free AI mock interview and get instant, specific feedback before the real one.
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The iOS Developer interview process
Swift, UIKit/SwiftUI, memory management and architecture — the iOS-engineering interview for product companies and mobile teams.
Swift fundamentals
Optionals, value vs reference types, closures and protocols.
UIKit / SwiftUI round
View lifecycle, Auto Layout and declarative UI.
Memory & concurrency
ARC, retain cycles, GCD and async/await.
Coding + design
DSA plus architecture (MVC/MVVM) and a small feature build.
Most-asked iOS Developer interview questions
12 of the questions iOS Developer candidates are asked most often in India. Practise answering each one out loud in your AI mock interview.
- 1. What is the difference between a struct and a class in Swift?
- 2. Explain optionals in Swift and the different ways to unwrap them safely.
- 3. What is ARC, and how do retain cycles happen? How do you break them?
- 4. What is the difference between strong, weak and unowned references?
- 5. Explain the difference between a delegate and a closure for callbacks.
- 6. What is the difference between frame and bounds in UIKit?
- 7. Explain Grand Central Dispatch and the difference between sync and async.
- 8. What is the difference between UIKit and SwiftUI?
- 9. Explain the iOS view-controller lifecycle.
- 10. What are protocols and protocol-oriented programming in Swift?
- 11. How do you persist data in iOS (UserDefaults vs Core Data vs files)?
- 12. What is the difference between escaping and non-escaping closures?
How to prepare for your iOS Developer interview
Master Swift fundamentals: value vs reference types, optionals, closures, generics and protocols.
Understand memory management deeply — ARC, retain cycles, and strong/weak/unowned — it's a favourite topic.
Know both UIKit (lifecycle, Auto Layout, delegates) and SwiftUI; be able to compare them.
Be comfortable with concurrency: GCD, operation queues and Swift's async/await.
Have an app on the App Store or a polished side project you can demo and discuss architecturally.
Practise other roles
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Interview prep guides
iOS Developer interview — FAQs
What questions are asked in a iOS Developer interview?
Common iOS Developer interview questions include: What is the difference between a struct and a class in Swift? Explain optionals in Swift and the different ways to unwrap them safely. What is ARC, and how do retain cycles happen? How do you break them? What is the difference between strong, weak and unowned references? Interviews usually run across 4 rounds — Swift fundamentals, UIKit / SwiftUI round, Memory & concurrency, Coding + design. Practice all of them with instant AI feedback using OnJob's free mock interview.
How many rounds are in a iOS Developer interview?
A typical iOS Developer interview has 4 rounds: Swift fundamentals (Optionals, value vs reference types, closures and protocols.); UIKit / SwiftUI round (View lifecycle, Auto Layout and declarative UI.); Memory & concurrency (ARC, retain cycles, GCD and async/await.); Coding + design (DSA plus architecture (MVC/MVVM) and a small feature build.).
How do I prepare for a iOS Developer interview?
To prepare for a iOS Developer interview: Master Swift fundamentals: value vs reference types, optionals, closures, generics and protocols. Understand memory management deeply — ARC, retain cycles, and strong/weak/unowned — it's a favourite topic. Know both UIKit (lifecycle, Auto Layout, delegates) and SwiftUI; be able to compare them. Then run a full AI mock interview on OnJob to rehearse out loud and get instant, specific feedback before the real thing.
What skills do I need for a iOS Developer role?
Core iOS Developer skills tested in interviews include Swift, UIKit, SwiftUI, Core Data, GCD, MVVM, Auto Layout. OnJob shows you exactly which of these skills stand between you and a 100% match on every live iOS Developer job.
Is OnJob's iOS Developer mock interview free?
Yes. OnJob's AI mock interview is free to start (₹0) and gives you instant feedback on your answers. Pro (₹99/month) adds unlimited interview-prep AI alongside recruiter tracking and unlimited applications.
Ace your iOS Developer interview
Rehearse every iOS Developer question out loud with OnJob's AI mock interview and get instant, specific feedback. Then apply to AI-matched jobs in one click — free to start.
Everything about iOS Developer on OnJob
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