Top iOS Interview Questions [2023]

iOS developers build applications for mobile devices powered by the iOS operating system. They build, test, and refine mobile applications for Apple iOS. Interviewing iOS candidates commonly consists of basic and advanced questions to assess technical ability. We sourced these questions from the iOS community based on developers’ own interview experience and what our clients found important to ask.

Could you use help hiring iOS developers? Scalable Path’s experienced Talent Acquisition team can help.

iOS Interview Questions and Answers

These are the types of questions typically asked during iOS interviews. We created them to help you test your understanding of the popular programming language, or guide your initial technical screening with iOS candidates.

How would you explain closures to a new Swift developer?
View Answer

State the difference between App ID and Bundle ID
View Answer

Explain how the Apple Developer Program membership uses certificates.
View Answer

Explain your experience with Accessibility tools on iOS
View Answer

Explain Mac Catalyst, its functionality, and give your thoughts on the overall integration between Apple’s operating systems.
View Answer

Please describe the four layers of the iOS architecture, and briefly explain the role of each layer. Think of the hardware as the bottom layer.
View Answer

Please list the possible states in which an iOS application can be. For each state, list the states to which the app can transition.
View Answer

What is ARC in the Swift programming language, what is it for, and how does it work?
View Answer

What is a lazy variable? Explain how they work.
View Answer

What does KVO mean? What considerations must be taken on Swift to achieve it?
View Answer

What is a phantom type in Swift? What are they for?
View Answer

What is Display P3, and what considerations should be taken with your assets and code when your app supports wide gamut displays?
View Answer

What does deep linking mean on iOS? What are your options to implement deep links, and what are the differences?
View Answer

What is the difference between self and Self in Swift? What are the main uses of both?
View Answer

What is a variadic function, and how do you implement one in Swift. How would you make a variadic function that accepts multiple types?
View Answer

Explain the difference between argument labels and parameter names in function parameters. Is it possible to write a function without a label? If so, how? Is it possible to write a function without a name? If so, how?
View Answer

Explain a common use case for the targetEnvironment() compilation condition and write a snippet of a conditional compilation block of code (you may omit statements and simply use comments inside the block)
View Answer

Describe the workflow for configuring in-app purchases
View Answer

Describe the differences and relationship between RealityKit and ARKit
View Answer

Explain the three phases of implementing Handoff in your app.
View Answer

This list isn't exhaustive, and interviewing typically includes an assessment of soft skills and technical ability through a take-home assignment or live coding exercise. You can learn more about hiring here.

Ready to grow your remote team?