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iOS Swift Developer interview questions & mock practice

A iOS Swift Developer interview in 2026 runs across 4 rounds — swift fundamentals, ios framework round, memory & concurrency, machine coding & culture fit. Below are the most-asked iOS Swift 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.

SwiftiOSUIKitSwiftUIAuto LayoutGrand Central DispatchXcodeGit
Free interview practice · iOS Swift Developer

Practise your iOS Swift Developer interview now — free

Step through the 12 most-asked iOS Swift Developer questions one at a time, under a timer, just like the real thing. Jot your answer, then reveal what a strong answer covers. No signup needed to practise.

Interview rounds

The iOS Swift Developer interview process

Swift, UIKit and SwiftUI, memory management and the iOS app lifecycle — the mobile interview for product companies and agencies shipping iOS apps in India.

1

Swift fundamentals

Optionals, value vs reference types, protocols, generics and closures.

2

iOS framework round

UIKit vs SwiftUI, view lifecycle, Auto Layout and navigation.

3

Memory & concurrency

ARC, retain cycles, GCD, async/await and the main thread.

4

Machine coding & culture fit

Build a small screen live; architecture choices and team fit.

Most-asked questions

Most-asked iOS Swift Developer interview questions

12 of the questions iOS Swift Developer candidates are asked most often in India. Practise answering each one out loud in your AI mock interview.

  1. 1. What are optionals in Swift, and what is the difference between optional binding, optional chaining and force unwrapping?
  2. 2. Explain the difference between a struct and a class in Swift, and when you would choose each.
  3. 3. What is ARC, and how do strong, weak and unowned references prevent retain cycles?
  4. 4. What is the difference between escaping and non-escaping closures?
  5. 5. Explain protocol-oriented programming and how protocol extensions work.
  6. 6. What is the difference between UIKit and SwiftUI, and how does SwiftUI manage state?
  7. 7. Explain the property wrappers State, Binding, ObservedObject and StateObject in SwiftUI.
  8. 8. How does Grand Central Dispatch work, and what is the difference between sync and async dispatch?
  9. 9. How does Swift's async/await model improve on completion-handler callbacks?
  10. 10. Describe the iOS app and view controller lifecycle.
  11. 11. What is the difference between frame and bounds in a UIView?
  12. 12. Tell me about a crash or retain cycle you debugged in a production iOS app.
How to prepare

How to prepare for your iOS Swift Developer interview

Be precise about value vs reference semantics — when copy-on-write kicks in, and why structs are the default in modern Swift.

Master memory management: ARC, retain cycles, capture lists in closures, and weak versus unowned references.

Know both UIKit and SwiftUI; many interviews expect you to compare them and explain SwiftUI's declarative state model.

Practice a small machine-coding screen — a list with networking — wiring async/await and clean state management.

Prepare a real story about debugging a crash, a leak, or a tricky Auto Layout issue using Instruments.

Practise other roles

iOS Swift Developer interview — FAQs

What questions are asked in a iOS Swift Developer interview?

Common iOS Swift Developer interview questions include: What are optionals in Swift, and what is the difference between optional binding, optional chaining and force unwrapping? Explain the difference between a struct and a class in Swift, and when you would choose each. What is ARC, and how do strong, weak and unowned references prevent retain cycles? What is the difference between escaping and non-escaping closures? Interviews usually run across 4 rounds — Swift fundamentals, iOS framework round, Memory & concurrency, Machine coding & culture fit. Practice all of them with instant AI feedback using OnJob's free mock interview.

How many rounds are in a iOS Swift Developer interview?

A typical iOS Swift Developer interview has 4 rounds: Swift fundamentals (Optionals, value vs reference types, protocols, generics and closures.); iOS framework round (UIKit vs SwiftUI, view lifecycle, Auto Layout and navigation.); Memory & concurrency (ARC, retain cycles, GCD, async/await and the main thread.); Machine coding & culture fit (Build a small screen live; architecture choices and team fit.).

How do I prepare for a iOS Swift Developer interview?

To prepare for a iOS Swift Developer interview: Be precise about value vs reference semantics — when copy-on-write kicks in, and why structs are the default in modern Swift. Master memory management: ARC, retain cycles, capture lists in closures, and weak versus unowned references. Know both UIKit and SwiftUI; many interviews expect you to compare them and explain SwiftUI's declarative state model. 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 Swift Developer role?

Core iOS Swift Developer skills tested in interviews include Swift, iOS, UIKit, SwiftUI, Auto Layout, Grand Central Dispatch, Xcode, Git. OnJob shows you exactly which of these skills stand between you and a 100% match on every live iOS Swift Developer job.

Is OnJob's iOS Swift 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.

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