Unlock Top Talent: 30+ Must-Ask Interview Questions for iOS Developers (2025 Update)

Keith Kipkemboi

iOS Developer

Mobile Engineer

Technical Recruiter

Swift

Xcode

SwiftUI

Pancake UIkit

Electronics

Unlock Top Talent: 30+ Must-Ask Interview Questions for iOS Developers (2025 Update)

Preparing for the iOS Developer Interview

Defining Your Needs: Skills and Experience Levels

Structuring the Interview Process

Creating a Consistent Evaluation Rubric

Technical Interview Questions for iOS Developers

Swift Programming Language

Objective-C (if applicable)

iOS Frameworks (UIKit, SwiftUI, Core Data, etc.)

Architecture and Design Patterns

Concurrency and Asynchronous Operations

Testing and Debugging

Version Control (Git)

API Integration and Networking

Behavioral and Situational Questions

Problem-Solving and Decision-Making

Teamwork and Collaboration

Adaptability and Learning

Past Projects and Experience

Coding Challenges and Practical Exercises

Live Coding Exercises

Take-Home Assignments

Code Review Simulation

Questions to Ask Senior vs. Junior iOS Developers

Focus for Junior Developers

Focus for Senior Developers

Red Flags to Watch Out For

Inability to Explain Concepts Clearly

Lack of Curiosity or Passion

Poor Problem-Solving Approach

Vague Answers About Past Experience

Conclusion: Selecting the Best iOS Developer

References

Unlock Top Talent: 30+ Must-Ask Interview Questions for iOS Developers (2025 Update)

The interview process is pivotal when you aim to hire iOS developers who can truly elevate your projects. Finding the right developer isn't just about technical skills—it's about discovering someone who can solve problems creatively and mesh well with your team. Understanding the true cost of hiring iOS developers is important, but asking the right questions ensures you invest wisely.

This guide provides a comprehensive list of interview questions—covering technical expertise, problem-solving abilities, and behavioral aspects—to help you identify top talent. These questions will help you gauge if a candidate is a good fit before you start considering where to find and hire the best iOS developers. Let's dive into the essential questions that separate great iOS developers from the rest.

Preparing for the iOS Developer Interview

Before you start firing off technical questions, you need a solid game plan. A well-structured interview process saves time and helps you make better hiring decisions. Think of it like building an app—you wouldn't start coding without understanding the requirements first.

Defining Your Needs: Skills and Experience Levels

Start by getting crystal clear on what you actually need. Are you looking for someone to maintain an existing Objective-C codebase? Or do you need a Swift expert to build a new app from scratch? Your project requirements will shape your entire interview approach.

Consider the specific frameworks and tools your project uses. If you're building a data-heavy app, Core Data experience might be crucial. For apps with complex UIs, SwiftUI expertise could be a must-have. Don't forget about the experience level—a junior developer might be perfect for routine tasks, while complex architectural decisions require senior-level thinking.

Write down your must-haves versus nice-to-haves. This clarity helps you avoid getting distracted by impressive but irrelevant skills during interviews.

Structuring the Interview Process

A multi-stage interview process works best for iOS developer roles. Start with a brief phone screening to verify basic qualifications and communication skills. This saves everyone time by filtering out obvious mismatches early.

Next comes the technical assessment. This could be a take-home project or a live coding session. Follow up with a deeper technical interview where you explore their problem-solving approach and technical knowledge. Finally, conduct a behavioral interview to assess cultural fit and soft skills.

Each stage should build on the previous one. The phone screen confirms they can do the job. The technical assessment shows how they do it. The behavioral interview reveals if they'll thrive in your environment.

Creating a Consistent Evaluation Rubric

Develop a scorecard before you interview anyone. This keeps your evaluation objective and helps you compare candidates fairly. Include categories like technical skills, problem-solving ability, communication, and cultural fit.

Rate each area on a simple scale—maybe 1 to 5. Add specific notes about what impressed you or raised concerns. This systematic approach prevents you from being swayed by charisma or forgetting key details when comparing multiple candidates.

Share the rubric with other interviewers on your team. Consistency across interviewers gives you more reliable data for making your final decision.

Technical Interview Questions for iOS Developers

Now for the meat of the interview—technical questions. These help you understand not just what candidates know, but how they think about iOS development challenges.

Swift Programming Language

Swift forms the backbone of modern iOS development. Start with fundamentals: "Explain the difference between value types and reference types in Swift." A solid developer should discuss structs versus classes and when to use each.

Ask about optionals: "How do optionals work in Swift, and why are they important?" Good answers will cover nil safety and different unwrapping techniques. Follow up with: "What's the difference between if-let and guard-let?"

Dive into memory management: "Explain ARC and how to prevent retain cycles." Look for mentions of weak and unowned references. Ask them to describe a scenario where they've dealt with memory leaks.

Test their understanding of advanced features: "When would you use generics?" or "Explain protocol-oriented programming in Swift." These questions reveal depth of knowledge beyond basic syntax.

Objective-C (if applicable)

If your codebase includes Objective-C, test for competency here too. "What are the key differences between Objective-C and Swift?" helps gauge their experience with both languages.

Ask about memory management pre-ARC: "Explain retain, release, and autorelease." While less relevant today, this shows historical knowledge and deep understanding.

For mixed codebases, try: "How do you bridge Objective-C code with Swift?" Look for mentions of bridging headers and the @objc attribute.

iOS Frameworks (UIKit, SwiftUI, Core Data, etc.)

Framework knowledge separates iOS developers from general programmers. Start broad: "Compare UIKit and SwiftUI. When would you choose one over the other?"

For UIKit specifically: "Explain the view controller lifecycle." They should mention viewDidLoad, viewWillAppear, and other key methods. Ask about Auto Layout: "How do you handle different screen sizes?"

Test Core Data knowledge if relevant: "Describe the Core Data stack." Look for understanding of managed object contexts, persistent stores, and fetch requests.

For networking: "How do you handle API calls in iOS?" Expect discussion of URLSession, async/await, and error handling strategies.

Architecture and Design Patterns

Architecture questions reveal how developers structure larger applications. "Explain MVC in iOS development" is a good starter. Follow with: "What are the limitations of MVC, and what alternatives exist?"

Ask about specific patterns: "When would you use delegation versus closures?" or "Explain the coordinator pattern." These show familiarity with iOS-specific design approaches.

Test their practical application: "Describe the architecture of your most recent iOS project." Listen for clear reasoning behind their choices, not just pattern names.

Concurrency and Asynchronous Operations

Modern iOS apps require solid concurrency skills. Start with: "Explain Grand Central Dispatch and when you'd use it." Look for understanding of queues, priorities, and thread safety.

Ask about modern approaches: "How does async/await improve asynchronous code?" They should discuss readability and error handling benefits.

Present a scenario: "How would you download multiple images without blocking the UI?" Good answers will mention background queues and updating UI on the main thread.

Testing and Debugging

Quality code requires testing. Ask: "Describe your approach to unit testing iOS apps." Look for mentions of XCTest, test doubles, and what they actually test.

For debugging: "Walk me through debugging a crash that only happens on users' devices." Strong candidates will mention crash logs, symbolication, and reproduction strategies.

Try: "How do you test asynchronous code?" This reveals deeper testing knowledge beyond basic assertions.

Version Control (Git)

Every developer needs Git skills. Keep it practical: "Describe your Git workflow for feature development." Listen for branching strategies and commit practices.

Ask about collaboration: "How do you handle merge conflicts?" Good answers include communication with team members, not just technical resolution.

Test problem-solving: "You accidentally committed sensitive data. How do you fix it?" This shows both Git knowledge and security awareness.

API Integration and Networking

Most iOS apps connect to backends. Ask: "How do you structure networking code in iOS apps?" Look for separation of concerns and error handling strategies.

Test modern approaches: "Explain Codable and how it simplifies JSON parsing." They should demonstrate practical usage, not just theoretical knowledge.

Present a challenge: "How do you handle API authentication and token refresh?" This reveals experience with real-world networking complexities.

Behavioral and Situational Questions

Technical skills only tell part of the story. Behavioral questions reveal how candidates work in real situations.

Problem-Solving and Decision-Making

Start with: "Tell me about the most challenging bug you've fixed." Listen for their debugging process, not just the solution. How did they approach the unknown?

Ask about trade-offs: "Describe a time you had to choose between code quality and meeting a deadline." There's no perfect answer—you're looking for thoughtful decision-making.

Try scenario questions: "Your app is crashing for 10% of users after an update. Walk me through your response." This shows crisis management and prioritization skills.

Teamwork and Collaboration

iOS developers rarely work alone. Ask: "How do you handle disagreements about technical approaches?" Look for respect for others' opinions and constructive resolution.

Test communication skills: "Explain a complex iOS concept to a non-technical stakeholder." Can they translate technical details into business value?

Explore mentorship: "Describe a time you helped a teammate solve a problem." This reveals teaching ability and team spirit.

Adaptability and Learning

iOS development evolves rapidly. Ask: "How do you stay current with iOS development trends?" Look for specific resources and learning strategies.

Test adaptability: "Tell me about a time you had to learn a new technology quickly." Focus on their learning process, not just the outcome.

Challenge them: "SwiftUI just made your UIKit expertise less relevant. How do you respond?" This reveals attitude toward change and continuous learning.

Past Projects and Experience

Dive deep into their portfolio: "Walk me through your favorite iOS project. What was your specific contribution?" Listen for passion and clear ownership of their work.

Ask about impact: "How did you measure the success of your iOS apps?" This shows business awareness beyond just coding.

Explore challenges: "What would you do differently if you rebuilt that project today?" Good developers learn from experience and evolve their approaches.

Coding Challenges and Practical Exercises

Theory only goes so far. Practical exercises show how candidates actually code.

Live Coding Exercises

Keep live coding focused and achievable. A simple task like "Build a view that displays a list of items from an API" tests multiple skills without overwhelming pressure.

Watch their process, not just the result. Do they clarify requirements? How do they handle being stuck? Can they explain their thinking while coding?

Provide a realistic environment. Let them use documentation—real developers don't memorize everything. You're testing problem-solving, not memorization.

Take-Home Assignments

Take-home projects allow deeper work without interview pressure. Design assignments that mirror real work—maybe building a simple feature or refactoring existing code.

Set clear expectations: time limits, evaluation criteria, and what you're looking for. Respect their time—keep assignments under 4-6 hours of work.

During review, ask them to explain their choices. Why this architecture? How would they extend the solution? This discussion often reveals more than the code itself.

Code Review Simulation

Show candidates a piece of iOS code with intentional issues. Ask them to review it as if a teammate submitted it. This tests technical knowledge and communication skills simultaneously.

Look for constructive feedback style. Do they explain why something is problematic? Can they suggest better alternatives? This exercise reveals how they'll work with your team.

Include various issue types—bugs, performance problems, and style violations. See if they prioritize critical issues over nitpicks.

Questions to Ask Senior vs. Junior iOS Developers

Different experience levels require different interview approaches. Tailor your questions to match the role level.

Focus for Junior Developers

For juniors, emphasize learning potential over current knowledge. Ask: "What iOS concept has been most challenging to learn, and how did you tackle it?"

Test fundamentals thoroughly. They should understand basic Swift syntax, simple UI creation, and debugging basics. Don't expect architectural expertise yet.

Look for enthusiasm and curiosity. Ask: "What iOS feature would you love to learn next?" Junior developers should be eager to grow.

Assess their ability to take feedback: "Tell me about a time you received constructive criticism on your code." You'll be mentoring them—make sure they're coachable.

Focus for Senior Developers

Senior developers need broader skills. Ask: "How would you architect a large-scale iOS app from scratch?" They should discuss modularization, dependency management, and scalability.

Test leadership abilities: "How do you ensure code quality across a team?" Look for mentions of code reviews, standards documentation, and mentoring approaches.

Explore strategic thinking: "How do you balance technical debt with feature development?" Senior developers should think beyond individual tasks to project health.

Ask about influence: "Describe a time you introduced a new technology or process to your team." This shows initiative and ability to drive improvements.

Red Flags to Watch Out For

Some warning signs suggest a candidate might not work out. Stay alert for these issues.

Inability to Explain Concepts Clearly

If candidates can't explain their code or technical concepts clearly, they'll struggle in team environments. iOS development requires constant communication—with designers, backend developers, and stakeholders.

Watch for rambling, unclear answers or inability to adjust explanations for different audiences. Good developers can explain complex ideas simply.

Lack of Curiosity or Passion

iOS development changes constantly. Candidates who show no interest in new technologies or learning will quickly become outdated.

Red flags include not knowing about recent iOS updates, having no side projects or learning goals, or seeming bored when discussing technical topics.

Poor Problem-Solving Approach

When faced with coding challenges, some candidates panic or give up quickly. Others might jump to solutions without understanding the problem.

Look for systematic thinking: understanding requirements, considering options, and explaining reasoning. Random guessing or inability to debug their own code are serious concerns.

Vague Answers About Past Experience

When candidates can't clearly describe their contributions to past projects, it might indicate limited involvement or exaggerated claims.

Be wary of answers like "we built an app" without specifics about their personal contributions. Good developers can articulate exactly what they built and why.

Conclusion: Selecting the Best iOS Developer

Finding the right iOS developer requires more than just checking technical boxes. You need someone who combines solid coding skills with problem-solving ability and team compatibility.

Use these questions as a starting point, but adapt them to your specific needs. The best interview feels like a technical discussion between colleagues, not an interrogation.

Remember that great iOS developers are evaluating you too. Show them interesting challenges, a supportive team environment, and growth opportunities. The interview process is your first chance to demonstrate why top talent should choose your company.

Take time to make the right choice. A great iOS developer can transform your app and elevate your entire team. A poor hire costs time, money, and team morale. Use these questions wisely, trust your evaluation process, and you'll build an iOS team that delivers exceptional results.