Swift · UIKit · SwiftUI

Practice iOS interviews with questions worth your time

Work through realistic prompts on concurrency, UIKit, SwiftUI, and how systems fit together — written for engineers preparing for phone screens, loops, and senior-level conversations.

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Intermediate

What's the difference between frame and bounds in iOS?

Beginner

What is a closure in Swift?

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Beginner Swift

What is the difference between let and var in Swift?

Explain that let creates an immutable binding while var creates a mutable one, then separate how that rule behaves for value types versus reference types

Memory

Intermediate SwiftUI

How do you implement MVVM in SwiftUI?

Contrast Combine-era ObservableObject MVVM with iOS 17+ @Observable MVVM, keeping the same Provider → ViewModel → View boundaries, DI, and testability rules

SwiftUI Architecture

Intermediate Concurrency

How do you make shared mutable state thread-safe in Swift?

Start with the race condition, then compare locks, semaphores, queues, barriers, and actors for protecting shared mutable state in real Swift code

Concurrency Thread Safety

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Swift

13 questions · Ownership, protocols, generics, concurrency, and language fundamentals

Concurrency

8 questions · Actors, async/await, isolation, Sendable, and data-race reasoning

UIKit

3 questions · View lifecycle, rendering, diffable data sources, and UIKit architecture

SwiftUI

3 questions · State, identity, data flow, and compositional UI design

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The Complete iOS Interview Question Bank

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The full set of frequently asked iOS interview prompts — Swift through SwiftUI, architecture, concurrency, coding interviews, and AI-era. Questions only.

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Beginner100 questions