Top 60+ iOS Interview Questions in 2023

A study conducted by Technosquare1 claims that in the year 2022, there were more than 218 billion apps downloaded, and this trend is going to continue in the upcoming years.

The technology's ongoing demand has created a need for iOS app developers. Yet, finding and recruiting talented iOS app developers is incredibly difficult.

Of course, you're probably thinking it is not hard to guess why, as it is a niche field, and assessing their technical skills is challenging.

That is true, but it is not the only reason why finding iOS app developers is difficult.

According to a report released by Apple2, there are approximately 30 million iOS developers, which can mean significant competition.

As a result, the only way to ensure you're hiring the right individual is to ask the right iOS interview questions to assess their technical abilities and learn more about their understanding of iOS. In this article, we've compiled a collection of 60+ iOS interview questions to help HR managers find the right applicant according to the role requirement.

So, let's get started!

What is exactly iOS?

Simply put, iOS is iPhone Operating System. It is an operating system for apple devices such as iPhones, iPad, and iPods. Besides that, iOS is commonly known for its intuitive and user-friendly interface.

What is the role of an iOS developer?

An iOS developer is in charge of creating, testing, and updating iOS apps for mobile devices. They are required to work with programming languages such as Objective-C, Swift, and others to guarantee that programs function well on Apple devices.

Consumers today expect more user-friendly and intuitive iOS applications than ever before. Plus, apple releases a new iOS version nearly every year, making the need for iOS developers even more critical for organizations.

Which Key technical skills are required for iOS Developer?

Mentioned below is the list of technical skills you should look for while hiring an iOS Developer: 

• Knowledge of the Swift and Objective-C programming languages.
• Working knowledge of Cocoa Touch, Cocoa, and other Apple frameworks.
• Familiarity with UIKit, Core Data, and Core Animation.
• Comprehend Apple's Human Interface Guidelines.
• Proficiency in offline storage, threading, and performance optimization.
• Understanding of RESTful APIs for connecting iOS applications to back-end services.
• Knowledge of open-source iOS ecosystems and standard task libraries.
• Proficiency in Apple's App Store submission, optimization, and release management processes.
• Understanding of third-party libraries and APIs.
• General knowledge of the mobile landscape, architectures, trends, and upcoming technologies.

 iOS basic interview questions for freshers

• Explain the Architecture of iOS.
• Do you know what property is in iOS?
• Can you explain the difference between atomic and nonatomic properties? What is the default for synthesized properties?
• Explain the different types of iOS Application States.
• How does Core Data work?
• State the difference between Android and iOS.
• What is deep linking in iOS?
• Explain what is GCD (Grand Central Dispatch) in iOS.
• What is ARC (Automatic Reference Counting)?
• Explain the difference between Cocoa and Cocoa Touch.
• Tell programming languages used for iOS development?
• What framework is utilized to build an application's interface for iOS?
• Write different ways to achieve concurrency in iOS.
• State the difference between App ID and Bundle ID.
• Explain the difference between assigning and retaining keywords.

iOS interview questions for Intermediate developers

• What are Design Patterns?
• How well do you understand assign and retain keywords?
• What different programming languages will you choose for iOS development?
• What is Objective-C in iOS?
• What are the data types in Objective-C?
• How is Bundle ID different from App ID?
• What is the Singleton Design Pattern?
• What are the features of Swift Programming Language?
• What is a Facade Design Pattern?
• Which framework will you leverage to develop the application interface for iOS?
• What is the difference between KVC and KVO?
• What is SpriteKit, and what is SceneKit?
• How to Prioritize Usability in Design?
• Describe managed object context and its function.
• What is meant by deadlock?

iOS interview questions for experienced

• Explain Objective-C in OS.
• Name the most important data types in Objective-C.
• What are the crucial features of Swift?
• Explain NSError in Swift.
• What is Enum or Enumerations in Swift?
• What do you mean by lazy property in iOS?
• Why are design patterns important? Name some of the popular design patterns used in iOS.
• What is the JSON framework supported by iOS?
• Explain iBeacons in iOS.
• Explain TDD (Test-Driven Development).
• Explain the function of the completion handler.
• State the difference between strong, weak, read-only, and copy.
• What do you mean by dynamic dispatch?
• How can you implement storage and persistence in iOS?
• What are synchronous and asynchronous tasks in iOS? In what way can you execute asynchronous tasks in iOS? 

If you are looking for more detailed iOS developer interview questions, look at this iOS programming test.

iOS technical interview questions

• What is meant by Enumerations or Enum?
• What do you understand by Memento Pattern?
• What do you know about TVMLKit?
• Explain the difference between 'bundle ID' and 'app ID.'
• When an app is launched, what are its state transitions like?
• List class hierarchy of a UIButton until NSObject.
• What is the use of application:willFinishLaunchingWithOptions and application:didFinishLaunchingWithOptions?
• Specify the three rendering options for JSON serialization.
• Give the benefit of KVC or Key-value coding.
• Why is 'reuseIdentifier' used?
• What is the difference between retaining and copying?
• What is a protocol, and how to define it?
• What is a Responder chain?
• Give a brief about the singleton pattern.
• What is meant by the 'defer' keyword?

How to evaluate the skills of an iOS developer?

In order to evaluate the technical as well as non-technical skills of iOS developers hiring managers are required to have a helicopter view of the iOS concepts and follow the necessary steps.

Step 1: Get familiar with the technical terms and their implementation process by asking technical questions during the interview.

Step 2: Identify the level of expertise required for the position you are trying to fill.

Step 3: Frame your interview questions based on the role you are trying to fulfill. For example, if you are trying to recruit iOS junior developer, frame your questions on basic concepts. However, if you are looking for a senior person, go for iOS technical interview questions.

Step 4: Next, take the help of someone knowledgeable in this domain in your organization.

The process outlined above is lengthy because that candidate might lose interest and look for another opportunity. Moreover, it has the possibility to create unconscious bias.

That's why many skill assessment portals are available to help you make skill-intelligent hiring decisions. Using this platform, you can skip wasting hours scheduling multiple interview calls and time frame technical interview questions.

iMocha is an AI-powered skill intelligence platform that enables you to hire candidates according to their skill set while adhering to the hiring prerequisites of the company.

You can utilize the following capabilities of the tool to make your hiring journey more seamless:

• An extensive skill library of 2500 skills ensures that test assessments are readily available on various skills such as iOS programming test, iOS Swift test, CISCO iOS test, Objective-C Test, React.js, C++, and more.
• Custom-creation of your test according to the individual requirement of your company.
• IT & technical recruiting, university recruitment, lateral hiring, and diversity hiring services.
• Robust reporting capabilities to help you make informed recruitment decisions based on comprehensive assessment results.
• Innovative coding simulators, automated video interview functions, and one-way video interview questions.
• Customizable performance metrics to skip traditional pass/fail grades to accurately assess candidates' suitability for any position.
• AI-LogicBox to easily track candidates' technical abilities without having to write lengthy code from scratch.

Conclusion

Overall, the iOS technical interview questions listed above can assist you in determining the candidates' required skills as per the role. But, if you want to save hiring time, you can use skill assessment tools to obtain detailed test reports on candidates' knowledge and skills in a data-driven format.

FAQs

What kind of questions are asked of an iOS developer?

iOS Developers are generally asked the following set of iOS interview questions:

• What is the difference between Swift and Objective-C?
• What are the main memory management techniques used in iOS?
• Explain the view hierarchy and view controller lifecycle.
• How would you debug a crash in an iOS application?
• How does Core Data work?
• What is the purpose of the Apple Push Notification Service?

What are the technical and non-technical skills required for an iOS developer?

An iOS developer is often expected to have the following technical and non-technical skills:

Technical Skills

• Objective-C
• Swift programming
• Mobile app IDEs
• App development frameworks
• Apple OS frameworks
• UI/UX design fundamentals

Non-technical Skills

• Problem-Solving Skills
• Communication Skills 
• Analytical Skills
• Time Management Skills
• Design Skills
• Project Management Skills

How to assess the technical skills of an iOS developer?

You can assess iOS developers' technical skills by asking iOS technical interview questions or simply utilizing skill assessment tools to obtain a comprehensive report on their abilities and expertise.

References

1. 8 iOS app development stats and facts for 2023 (2022)

https://www.techosquare.com/ecommerce-playbook/ios-app-development-stats-facts

2. Apple Press Release (2021)

https://www.apple.com/newsroom/2021/08/apple-us-developers-agree-to-app-store-updates/