Interview Guide for

iOS Developer

This comprehensive interview guide provides a structured approach to hiring top iOS Developers. With carefully designed interview questions, work samples, and competency assessments, your team will be well-equipped to identify candidates who not only possess technical expertise but also demonstrate the essential behavioral competencies required for success in mobile development positions.

How to Use This Guide

This interview guide serves as a foundation for creating a consistent, objective hiring process for iOS Developer candidates. To get the most out of this resource:

Customize: Adapt the questions and competencies to align with your specific technical requirements and company culture.
Collaborate: Share this guide with your interview team to ensure everyone understands the evaluation criteria and interview structure.
Be Consistent: Use the same core questions with all candidates to enable fair comparisons.
Dive Deeper: Leverage the follow-up questions to explore candidates' experiences in greater depth, revealing their true capabilities beyond rehearsed answers.
Score Independently: Have each interviewer complete their scorecard before discussing the candidate to prevent groupthink and capture diverse perspectives.

For more on creating effective interviews, check out our blog post on conducting job interviews or explore our AI interview guide generator for customized solutions.

Job Description

iOS Developer

About [Company]

[Company] is a [Industry] company located in [Location]. We are passionate about [Company Mission/Values] and are dedicated to creating innovative and high-quality products. Join our team and be a part of a dynamic and collaborative environment where you can contribute to [Company Achievements/Impact].

The Role

As an iOS Developer at [Company], you will be responsible for designing, developing, and maintaining our mobile applications for the iOS platform. You will work closely with a team of engineers, designers, and product managers to build and deliver engaging and user-friendly experiences for our users. This role is crucial for our ongoing mobile strategy and directly impacts our users' experience with our products.

Key Responsibilities

Design, develop, and maintain iOS applications for [Company Products/Services]
Write clean, efficient, and well-documented code
Collaborate with cross-functional teams to define, design, and ship new features
Identify and fix bugs and performance issues
Implement unit and UI tests to ensure code quality and reliability
Stay up-to-date with the latest iOS development trends and best practices
Participate in code reviews and provide constructive feedback
Contribute to continuous improvement of development processes
Adhere to coding standards and style guidelines

What We're Looking For

[Number]+ years of professional experience in iOS development
Strong proficiency in Swift and/or Objective-C
Solid understanding of iOS SDK, frameworks, and design patterns (MVC, MVVM)
Experience with UIKit, Core Data, and other relevant iOS technologies
Experience with RESTful APIs and JSON parsing
Familiarity with version control systems (Git)
Strong problem-solving and debugging skills
Excellent communication and collaboration skills
Ability to work independently and as part of a team
Demonstrated passion for mobile development and continuous learning
Published apps on the App Store (preferred)

Why Join [Company]

At [Company], we offer an environment where you can grow professionally while working on challenging projects that make a difference. Our collaborative culture encourages innovation and creative problem-solving.

Competitive salary: [Compensation Range]
Comprehensive benefits package including health insurance and retirement plans
Professional development opportunities
Flexible work arrangements
Collaborative and innovative team environment

Hiring Process

We've designed our hiring process to be thorough yet efficient, allowing us to make quick decisions while getting to know you well.

Initial Screening: A brief call with our recruiter to discuss your experience and interest in the role.
Coding Exercise: A take-home coding exercise that demonstrates your iOS development skills.
Technical Discussion: A deeper conversation about your experience and approach to iOS development with our hiring manager.
Team Interview: Meet with our engineering team to discuss technical competencies and problem-solving approaches.
Cultural Fit Interview: Connect with cross-functional team members to explore how you'd work within our collaborative environment.

Ideal Candidate Profile (Internal)

Role Overview

The iOS Developer is responsible for designing, developing, and maintaining our mobile applications for the iOS platform. This role requires technical proficiency in iOS development, collaboration skills to work effectively with cross-functional teams, and attention to detail to ensure high-quality code. The ideal candidate demonstrates strong problem-solving abilities, a passion for continuous learning, and adaptability to keep pace with evolving technologies.

Essential Behavioral Competencies

Technical Problem-Solving: Ability to systematically analyze complex technical issues, debug effectively, and implement optimal solutions that balance performance, user experience, and code maintainability.

Continuous Learning: Proactively stays current with iOS development trends, frameworks, and best practices; demonstrates eagerness to expand technical knowledge and skills.

Collaboration and Communication: Effectively communicates technical concepts to both technical and non-technical stakeholders; works productively in cross-functional teams to achieve shared objectives.

Attention to Detail: Maintains a high standard of code quality through careful consideration of edge cases, thorough testing, and adherence to established guidelines and best practices.

Adaptability: Readily adjusts to changing requirements, priorities, and technologies; demonstrates flexibility in approach while maintaining productivity and code quality.

Desired Outcomes

Develop and maintain high-quality, performant iOS applications that meet user needs and business requirements
Contribute to the technical architecture and design decisions for scalable, maintainable iOS applications
Reduce bug counts and technical debt through implementation of best practices and proactive code improvements
Collaborate effectively with cross-functional teams to deliver features on time and to specification
Stay current with iOS platform changes and proactively implement relevant new technologies and methodologies

Ideal Candidate Traits

Demonstrates passion for mobile development through personal projects, contributions to open-source, or published apps
Shows initiative in proposing technical improvements and solving challenging problems
Balances pragmatism with technical excellence, making appropriate tradeoffs to meet business objectives
Communicates technical concepts clearly to both technical and non-technical stakeholders
Takes ownership of their work and demonstrates accountability for outcomes
Exhibits curiosity and willingness to learn new technologies and approaches
Works effectively both independently and as part of a team
Values feedback and continuously improves based on it

Screening Interview

Directions for the Interviewer

This initial screening interview aims to quickly assess whether the candidate meets the basic qualifications for the iOS Developer role and should proceed to the next stages. Focus on verifying their technical experience with iOS development, understanding their career trajectory, and evaluating their communication skills. This interview should take approximately 30 minutes. Plan to spend the last 5 minutes answering any questions the candidate may have about the role or company.

Keep the conversation flowing naturally while covering all the essential areas. Listen for concrete examples of their experience rather than theoretical knowledge. Pay attention to how they communicate technical concepts, as this is indicative of how they will collaborate with cross-functional teams.

Directions to Share with Candidate

During this conversation, I'll be asking about your experience with iOS development, your technical skills, and your career goals. This helps us understand if this role aligns with your background and interests. Feel free to ask any questions you have about the position or [Company] at the end of our discussion.

Interview Questions

Tell me about your experience with iOS development. What kinds of applications have you built and what was your role in those projects?

Areas to Cover

Types of iOS applications they've worked on
Specific responsibilities they held
Size and complexity of the projects
Their contribution to the team effort
Technologies and frameworks utilized
Challenges faced and how they were overcome

Possible Follow-up Questions

What was the most complex iOS app you've worked on and what made it challenging?
How did you approach architecture decisions in your previous projects?
What frameworks or libraries did you find most useful in your work?
How did you collaborate with designers and product managers on these projects?

Describe your proficiency with Swift and/or Objective-C. Which do you prefer and why?

Areas to Cover

Level of experience with each language
Understanding of language-specific features and paradigms
Comfort with latest language versions and features
Practical examples of how they've applied their language knowledge
Rationale for language preference based on technical considerations

Possible Follow-up Questions

How do you stay current with the latest Swift updates?
Can you give an example of a Swift feature you've found particularly useful?
How would you approach a codebase that mixes Swift and Objective-C?
What resources do you use to improve your programming skills?

How do you ensure your code is maintainable, scalable, and performant? Can you give specific examples?

Areas to Cover

Code organization and architecture patterns they employ
Testing strategies and practices
Performance optimization techniques
Documentation approaches
Code review processes they've participated in
Examples of refactoring or improving existing code

Possible Follow-up Questions

What design patterns do you typically use in iOS development?
How do you approach testing in your development process?
What tools do you use to monitor or improve app performance?
How do you handle technical debt in existing codebases?

Walk me through how you approach debugging a complex issue in an iOS app.

Areas to Cover

Systematic debugging methodology
Tools they use for debugging
How they isolate problems
Communication with team members during debugging
Examples of particularly challenging bugs they've solved
How they document issues and solutions

Possible Follow-up Questions

What debugging tools do you find most useful?
How do you approach intermittent or difficult-to-reproduce bugs?
Can you share an example of a particularly challenging bug you solved?
How do you ensure the same issue doesn't recur after fixing it?

Tell me about your experience working with external APIs and integrating them into iOS applications.

Areas to Cover

Types of APIs they've worked with
Their approach to API integration
Error handling and resilience strategies
Authentication methods they've implemented
Challenges faced during API integration
Performance considerations for network operations

Possible Follow-up Questions

How do you structure your networking code?
What libraries or tools do you prefer for API integration?
How do you handle API version changes or deprecations?
How do you test API integrations effectively?

What are you looking for in your next role and what interests you about this position?

Areas to Cover

Career goals and aspirations
What motivates them professionally
Skills they want to develop
Work environment preferences
Alignment with company values and mission
Understanding of the role and its responsibilities

Possible Follow-up Questions

What aspects of iOS development are you most passionate about?
How does this role fit into your long-term career plans?
What kind of team environment do you thrive in?
What questions do you have about our company or the role?

Interview Scorecard

Technical Experience

0: Not Enough Information Gathered to Evaluate
1: Limited iOS development experience, lacks depth in core technologies
2: Some iOS development experience but gaps in key areas
3: Solid iOS development experience with demonstrated proficiency
4: Extensive iOS development experience with mastery of multiple frameworks

Programming Knowledge

0: Not Enough Information Gathered to Evaluate
1: Basic understanding of Swift/Objective-C with significant gaps
2: Working knowledge of Swift/Objective-C but limited depth
3: Strong proficiency in Swift/Objective-C with good understanding of language features
4: Expert-level knowledge of Swift/Objective-C with nuanced understanding of language intricacies

Problem-Solving Abilities

0: Not Enough Information Gathered to Evaluate
1: Struggles to articulate problem-solving approaches
2: Can solve straightforward problems but may struggle with complexity
3: Demonstrates solid problem-solving methodology and technical troubleshooting
4: Exceptional problem-solving skills with creative approaches to complex challenges

Communication Skills

0: Not Enough Information Gathered to Evaluate
1: Difficulty expressing technical concepts clearly
2: Adequate communication but room for improvement in clarity or conciseness
3: Communicates technical concepts clearly and effectively
4: Outstanding communication with ability to adjust style for different audiences

Develop and maintain high-quality iOS applications

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on limited technical skills or experience
2: Likely to Partially Achieve Goal with supervision and guidance
3: Likely to Achieve Goal with demonstrated relevant experience
4: Likely to Exceed Goal with exceptional track record and expertise

Contribute to technical architecture and design decisions

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on limited architectural experience
2: Likely to Partially Achieve Goal with support from senior team members
3: Likely to Achieve Goal with demonstrated design decision experience
4: Likely to Exceed Goal with exceptional architecture expertise

Collaborate effectively with cross-functional teams

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on communication challenges or solo work preference
2: Likely to Partially Achieve Goal with adequate team skills
3: Likely to Achieve Goal with good collaborative experience
4: Likely to Exceed Goal with exceptional team collaboration history

Stay current with iOS platform changes

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on lack of learning initiative
2: Likely to Partially Achieve Goal with some professional development
3: Likely to Achieve Goal with demonstrated learning habits
4: Likely to Exceed Goal with exceptional commitment to staying current

Overall Recommendation

1: Strong No Hire - Significant gaps in technical skills or experience
2: No Hire - Does not meet key requirements for the role
3: Hire - Meets requirements and likely to succeed in the role
4: Strong Hire - Exceptional candidate who exceeds requirements

Coding Exercise (Work Sample)

Directions for the Interviewer

This coding exercise is designed to assess the candidate's practical iOS development skills, coding style, problem-solving approach, and attention to detail. The exercise should be challenging enough to differentiate skill levels but straightforward enough to be completed in a reasonable time frame.

Send the exercise instructions to the candidate and allow them 2-3 days to complete it. Review their submission before the follow-up discussion. During the discussion, focus on understanding their thought process, architectural decisions, and how they approached challenges.

Keep in mind that the goal is not just to evaluate their code, but also their ability to explain their decisions, handle feedback, and discuss alternative approaches. This exercise helps assess multiple competencies beyond just coding ability.

Directions to Share with Candidate

We'd like you to complete a coding exercise that demonstrates your iOS development skills. This is an opportunity to show us your coding style, architecture decisions, and problem-solving approach. Please take 2-3 days to complete this project, and then we'll review it together during our next conversation.

Exercise: Build a Simple Weather App

Create a simple iOS application that displays weather information. The app should:

Allow users to search for a city
Display current weather conditions (temperature, conditions, etc.)
Show a 5-day forecast
Save recently searched cities for quick access
Handle errors appropriately

You may use any public weather API (like OpenWeatherMap, which has a free tier). Please implement the app using Swift and UIKit. Feel free to use third-party libraries if you can justify their inclusion, but the core functionality should be your own work.

When submitting your code:

Include a README with instructions on how to build and run the app
Explain any architectural decisions or patterns you used
Note any challenges you encountered and how you solved them
Describe what you would improve with more time

We'll discuss your implementation during our next interview.

Interview Scorecard

Code Quality

0: Not Enough Information Gathered to Evaluate
1: Code is difficult to read, poorly structured, or contains many issues
2: Code is functional but has inconsistent style or some structural problems
3: Clean, well-organized code that follows standard conventions
4: Exceptional code quality with elegant solutions and excellent organization

Architecture Design

0: Not Enough Information Gathered to Evaluate
1: Poor architectural choices that hinder maintainability or scalability
2: Basic architecture that works but lacks sophistication or future-proofing
3: Well-designed architecture that follows established patterns
4: Excellent architecture demonstrating deep understanding of iOS design patterns

Feature Implementation

0: Not Enough Information Gathered to Evaluate
1: Missing multiple required features or major functionality issues
2: All features implemented but with some limitations or minor issues
3: Complete implementation of all required features with solid functionality
4: Complete implementation with additional refinements beyond requirements

User Experience

0: Not Enough Information Gathered to Evaluate
1: Poor UI/UX with usability issues or significant design problems
2: Functional UI but lacking refinement or intuitive design
3: Good UI/UX that follows iOS design principles
4: Excellent UI/UX with thoughtful touches that enhance usability

Error Handling

0: Not Enough Information Gathered to Evaluate
1: Poor or minimal error handling
2: Basic error handling but edge cases not well-addressed
3: Comprehensive error handling with good user feedback
4: Exceptional error handling with graceful degradation and recovery

Develop and maintain high-quality iOS applications

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on code quality issues
2: Likely to Partially Achieve Goal with improvements needed
3: Likely to Achieve Goal with demonstrated coding skills
4: Likely to Exceed Goal with exceptional app development skills

Contribute to technical architecture and design decisions

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on poor architectural choices
2: Likely to Partially Achieve Goal with basic architectural understanding
3: Likely to Achieve Goal with good architecture implementation
4: Likely to Exceed Goal with excellent architectural decisions

Reduce bug counts and technical debt

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on code issues or poor practices
2: Likely to Partially Achieve Goal with some good practices
3: Likely to Achieve Goal with clean, well-tested code
4: Likely to Exceed Goal with exceptionally maintainable code

Stay current with iOS platform changes

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on outdated approaches
2: Likely to Partially Achieve Goal with some modern practices
3: Likely to Achieve Goal with current best practices
4: Likely to Exceed Goal with cutting-edge iOS techniques

Overall Recommendation

1: Strong No Hire - Significant issues with code quality or missing features
2: No Hire - Does not meet expectations for iOS development skills
3: Hire - Demonstrates solid iOS development skills
4: Strong Hire - Exceptional technical skills and implementation

Chronological Interview

Directions for the Interviewer

This interview is designed to understand the candidate's career progression, growth, challenges, and achievements over time. Focus on their iOS development experience, but also explore their broader software development background. The goal is to understand not just what they've done, but how they've grown and what they've learned from each experience.

Start with their earliest relevant role and work forward chronologically. For each position, explore responsibilities, achievements, challenges, and reasons for transitions. This approach helps reveal patterns in their career, their ability to learn and adapt, and how they've progressed in their technical and professional development.

Pay close attention to the context of their achievements, the complexity of problems they've solved, and how they've collaborated with others. This interview should take approximately 60 minutes, with the last 10 minutes reserved for candidate questions.

Directions to Share with Candidate

In this conversation, we'll review your professional history chronologically, focusing on your iOS and software development experience. For each role, I'll ask about your responsibilities, key projects, technical challenges, and what you learned. This helps us understand your growth as a developer and how your experiences have shaped your current skills and approach.

Interview Questions

Let's start with an overview of your career. What drew you to iOS development and how has your journey evolved?

Areas to Cover

Initial interest in mobile or iOS development
Key milestones in their career progression
Overall career trajectory and focus areas
Major transitions or pivots in their career
Growth in responsibilities over time
Long-term career goals

Possible Follow-up Questions

What aspects of iOS development do you find most engaging?
How has your perspective on mobile development changed over time?
What skills have you found most valuable throughout your career?
What career achievements are you most proud of?

Starting with your first relevant role at [Previous Company], what were your main responsibilities and what technical challenges did you face?

Areas to Cover

Specific role and responsibilities
Team structure and their position within it
Technologies and frameworks used
Key projects they contributed to
Technical challenges encountered
Growth and learning during this period
Reason for leaving

Possible Follow-up Questions

What was the most complex iOS feature you implemented in this role?
How did you collaborate with other team members?
What did you learn about iOS development during this time?
How did you handle disagreements about technical decisions?

Tell me about your experience at [Next Company]. How did your responsibilities change and what were your major accomplishments?

Areas to Cover

Evolution of responsibilities compared to previous role
Increased technical complexity or scope
Leadership or mentoring responsibilities
Major projects and their impact
Technical innovations or improvements introduced
Challenges faced and how they were overcome
Reason for transition to next role

Possible Follow-up Questions

How did you measure the success of your work?
What technical debt or challenges did you inherit, and how did you address them?
Can you describe a situation where you had to learn a new technology quickly?
What feedback did you receive about your performance in this role?

Moving on to [Recent/Current Company], what has been your focus and what technical problems have you solved?

Areas to Cover

Current role scope and responsibilities
Recent projects and technical challenges
Architectural decisions and their outcomes
Performance optimization work
Team collaboration and leadership
Technologies and methodologies employed
Growth and development in this role

Possible Follow-up Questions

What are you currently working on, and what makes it challenging?
How have you influenced technical decisions in your current role?
What improvements have you made to development processes?
How do you balance technical debt against new feature development?

Looking across your career, how have you kept up with the evolving iOS platform and what approaches to development have you found most effective?

Areas to Cover

Learning strategies and resources
Adaptation to new iOS versions and technologies
Evolution of their development practices
Technical perspectives and preferences that have changed
Consistent principles they've maintained
Professional development activities

Possible Follow-up Questions

How do you evaluate new iOS features or frameworks before adopting them?
What iOS-related blogs, forums, or resources do you follow?
Have you contributed to any open-source iOS projects or the broader community?
How do you decide when to refactor existing code versus maintaining current patterns?

Which job in your past does this iOS Developer role remind you of most, and why?

Areas to Cover

Similarities in technical requirements
Comparable team structures or dynamics
Related challenges or problem domains
How past experiences might apply to this role
Lessons learned that would be valuable
Their understanding of the current role's requirements

Possible Follow-up Questions

What aspects of that experience would you bring to this role?
What would you do differently based on what you learned?
How do you think this role might be more challenging?
What excites you about applying your experience to our challenges?

Interview Scorecard

Technical Growth

0: Not Enough Information Gathered to Evaluate
1: Limited progression in technical skills throughout career
2: Some advancement in technical capabilities but gaps in key areas
3: Clear progression of technical skills with relevant iOS expertise
4: Exceptional technical growth with demonstrated mastery across various projects

Problem-Solving Evolution

0: Not Enough Information Gathered to Evaluate
1: Limited examples of solving complex problems
2: Some evidence of tackling challenging issues with moderate success
3: Strong track record of effectively addressing complex technical challenges
4: Exceptional problem-solving history with innovative approaches to difficult issues

Leadership and Collaboration

0: Not Enough Information Gathered to Evaluate
1: Primarily individual contributor with minimal team collaboration
2: Some collaborative experience but limited leadership
3: Good balance of technical contribution and team collaboration
4: Strong history of technical leadership and effective cross-functional collaboration

Career Progression

0: Not Enough Information Gathered to Evaluate
1: Unclear or stagnant career trajectory
2: Modest progression with some gaps or lateral moves
3: Steady career advancement with increasing responsibilities
4: Impressive career trajectory with significant growth in scope and impact

Adaptability to Change

0: Not Enough Information Gathered to Evaluate
1: Resistance to changing technologies or methodologies
2: Slow but eventual adaptation to technical changes
3: Embraces new technologies and approaches appropriately
4: Proactively drives adoption of new technologies when beneficial

Develop and maintain high-quality iOS applications

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on prior work quality
2: Likely to Partially Achieve Goal with additional guidance
3: Likely to Achieve Goal based on demonstrated experience
4: Likely to Exceed Goal with exceptional prior achievements

Contribute to technical architecture and design decisions

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on limited architectural experience
2: Likely to Partially Achieve Goal with growing architectural skills
3: Likely to Achieve Goal with good architectural background
4: Likely to Exceed Goal with strong architecture experience

Reduce bug counts and technical debt

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on maintenance history
2: Likely to Partially Achieve Goal with some quality focus
3: Likely to Achieve Goal with demonstrated code quality emphasis
4: Likely to Exceed Goal with exceptional quality improvement history

Collaborate effectively with cross-functional teams

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on limited collaboration experience
2: Likely to Partially Achieve Goal with some team experience
3: Likely to Achieve Goal with good collaboration history
4: Likely to Exceed Goal with exceptional cross-functional experience

Overall Recommendation

1: Strong No Hire - Significant concerns about experience or capabilities
2: No Hire - Experience doesn't align well with our needs
3: Hire - Good experience that matches our requirements
4: Strong Hire - Exceptional candidate with ideal experience

Technical Competency Interview

Directions for the Interviewer

This interview evaluates the candidate's technical depth and breadth in iOS development. Focus on assessing their knowledge of iOS frameworks, design patterns, problem-solving approaches, and engineering best practices. Questions should probe beyond surface-level understanding to reveal how they think about technical problems and implement solutions.

The goal is to determine whether the candidate has the technical competencies needed for success in this role. Listen for signs of depth, nuance, and practical experience in their answers. Pay attention to how they approach problems, their understanding of tradeoffs, and their ability to explain complex technical concepts clearly.

This interview should take approximately 60 minutes. Allow time at the end for the candidate to ask questions about technical aspects of the role or team.

Directions to Share with Candidate

In this technical discussion, we'll explore your iOS development knowledge and experience in more depth. I'll ask about your understanding of iOS frameworks, architecture patterns, and how you approach specific technical challenges. This helps us understand your technical capabilities and how you think about software development problems.

Interview Questions

Describe your experience with different iOS architectural patterns (MVC, MVVM, etc.). Which do you prefer and why? (Technical Problem-Solving, Continuous Learning)

Areas to Cover

Understanding of common iOS architectural patterns
Practical experience implementing different patterns
Awareness of strengths and weaknesses of each approach
Decision-making process for choosing architecture
Ability to adapt architecture to project requirements
Examples from their past work

Possible Follow-up Questions

How have you handled the evolution of an app's architecture over time?
What challenges have you encountered when implementing MVVM?
How do you test applications built with these different patterns?
How do you decide when to use a particular pattern for a new project?

Walk me through how you would optimize the performance of an iOS application that's experiencing UI lag and memory issues. (Technical Problem-Solving, Attention to Detail)

Areas to Cover

Systematic approach to performance debugging
Knowledge of iOS performance profiling tools
Understanding of common performance bottlenecks
Memory management concepts and practices
UI rendering optimization techniques
Balancing performance with code maintainability

Possible Follow-up Questions

What tools would you use to identify memory leaks?
How would you approach image loading and caching?
What strategies have you used to optimize table/collection view scrolling?
How do you prioritize which performance issues to address first?

How do you approach building reusable components or frameworks for iOS applications? (Technical Problem-Solving, Collaboration and Communication)

Areas to Cover

Experience creating reusable components
API design principles and considerations
Documentation approaches
Versioning and compatibility strategies
Testing methodologies for reusable code
Balance between flexibility and simplicity

Possible Follow-up Questions

How do you determine what should be a reusable component?
How do you handle backward compatibility when updating components?
How do you document your components for other developers?
Can you give an example of a component you've built that was particularly successful?

Explain your experience with Core Data and other persistence solutions. What factors influence your choice of storage solution for an iOS app? (Technical Problem-Solving, Adaptability)

Areas to Cover

Experience with various iOS persistence options
Understanding of Core Data architecture and capabilities
Knowledge of alternatives (Realm, SQLite, UserDefaults, etc.)
Decision factors for choosing a persistence solution
Data migration strategies
Performance considerations

Possible Follow-up Questions

How have you handled Core Data migrations?
When would you choose Realm over Core Data, or vice versa?
How do you test your persistence layer?
How do you handle sync between local storage and remote APIs?

Describe how you stay current with iOS development best practices and new technologies. Give an example of a recent iOS feature or technology you've adopted and how you integrated it. (Continuous Learning, Adaptability)

Areas to Cover

Learning strategies and resources
Evaluation process for new technologies
Balance between adopting new features and maintaining stability
Example of technology adoption and implementation
Challenges faced during implementation
Outcomes and lessons learned

Possible Follow-up Questions

What iOS blogs, podcasts, or communities do you follow?
How do you decide when to adopt a new iOS feature versus waiting?
What's your approach to learning a completely new framework?
How do you balance staying current with maintaining productivity?

How do you approach testing in iOS development? What types of tests do you write and what tools do you use? (Attention to Detail, Technical Problem-Solving)

Areas to Cover

Testing philosophy and strategy
Experience with unit, integration, and UI testing
Familiarity with XCTest and other testing frameworks
Test-driven development experience
Mocking and stubbing approaches
CI/CD integration for testing

Possible Follow-up Questions

How do you decide what to test and how much test coverage is enough?
How do you handle testing network requests?
What's your approach to UI testing and handling flaky tests?
How have you improved test performance in larger projects?

Interview Scorecard

iOS Framework Knowledge

0: Not Enough Information Gathered to Evaluate
1: Limited knowledge of essential iOS frameworks
2: Familiar with common frameworks but lacks depth
3: Strong understanding of iOS frameworks with practical experience
4: Expert-level knowledge across multiple iOS frameworks

Architecture and Design

0: Not Enough Information Gathered to Evaluate
1: Basic grasp of architectural concepts with minimal application
2: Understands common patterns but limited experience implementing them
3: Strong architectural knowledge with practical implementation experience
4: Exceptional architectural understanding with nuanced views on tradeoffs

Performance Optimization

0: Not Enough Information Gathered to Evaluate
1: Limited knowledge of performance considerations
2: Aware of common optimization techniques but limited experience
3: Strong grasp of performance optimization with practical experience
4: Expert-level understanding of iOS performance with demonstrated success

Testing Proficiency

0: Not Enough Information Gathered to Evaluate
1: Minimal experience with testing
2: Basic testing knowledge but inconsistent application
3: Strong testing approach with good coverage strategies
4: Comprehensive testing methodology with advanced techniques

Technical Problem-Solving

0: Not Enough Information Gathered to Evaluate
1: Struggles with complex technical challenges
2: Can solve straightforward problems but may miss edge cases
3: Strong problem-solving skills with systematic approach
4: Exceptional problem-solving abilities with elegant solutions

Develop and maintain high-quality iOS applications

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on technical limitations
2: Likely to Partially Achieve Goal with support
3: Likely to Achieve Goal with demonstrated technical competence
4: Likely to Exceed Goal with exceptional technical expertise

Contribute to technical architecture and design decisions

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on limited architectural knowledge
2: Likely to Partially Achieve Goal with growing capabilities
3: Likely to Achieve Goal with solid architectural understanding
4: Likely to Exceed Goal with outstanding architectural expertise

Reduce bug counts and technical debt

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on quality approach
2: Likely to Partially Achieve Goal with basic practices
3: Likely to Achieve Goal with strong quality focus
4: Likely to Exceed Goal with exceptional quality practices

Stay current with iOS platform changes

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on learning approach
2: Likely to Partially Achieve Goal with some continuing education
3: Likely to Achieve Goal with good learning habits
4: Likely to Exceed Goal with exceptional dedication to staying current

Overall Recommendation

1: Strong No Hire - Significant technical deficiencies
2: No Hire - Technical skills don't meet our requirements
3: Hire - Strong technical skills that meet our needs
4: Strong Hire - Exceptional technical capabilities

Behavioral Competency Interview

Directions for the Interviewer

This interview focuses on assessing the candidate's behavioral competencies that are essential for success in this iOS Developer role. The questions target specific competencies: Collaboration and Communication, Adaptability, Continuous Learning, and Attention to Detail. These are critical for working effectively within our engineering team and delivering high-quality mobile applications.

Use the STAR method to guide candidates through their responses: Situation, Task, Action, and Result. Listen for concrete examples rather than hypothetical approaches. Pay attention to how they interacted with others, handled challenges, and what they learned from their experiences. The goal is to understand how they would likely behave in similar situations at [Company].

This interview should take approximately 45-60 minutes. Allow time at the end for the candidate to ask questions about the team culture and working environment.

Directions to Share with Candidate

In this conversation, I'll ask you about specific situations you've encountered in your past work. For each question, please share a real example, describing the situation, your role, the actions you took, and the outcome. These examples help us understand how you approach collaboration, adapt to change, continue learning, and pay attention to detail in your work.

Interview Questions

Tell me about a time when you had to collaborate with designers and product managers to implement a challenging feature in an iOS app. How did you handle different perspectives to achieve the best outcome? (Collaboration and Communication)

Areas to Cover

Nature of the feature and technical challenges
Different perspectives among team members
How they communicated technical constraints
How they incorporated feedback
Strategies used to build consensus
Result of the collaboration
Lessons learned from the experience

Possible Follow-up Questions

How did you handle disagreements during this process?
What techniques did you use to communicate technical concepts to non-technical team members?
How did you balance technical considerations with design or product requirements?
What would you do differently if you faced a similar situation again?

Describe a situation where you had to adapt to a significant change in project requirements or technology while developing an iOS application. (Adaptability)

Areas to Cover

Nature of the change and its impact
Initial reaction to the change
Steps taken to adapt
How they reprioritized work
Communication with stakeholders
Challenges faced during adaptation
Outcome and lessons learned

Possible Follow-up Questions

How did you manage your time and priorities during this transition?
What strategies helped you learn the new requirements or technology quickly?
How did you help others on your team adapt to the change?
How has this experience influenced how you approach changes now?

Tell me about a time when you identified and resolved a subtle bug or performance issue in an iOS app that others had missed. (Attention to Detail)

Areas to Cover

Nature of the bug or performance issue
How they discovered the problem
Their debugging approach
Tools or techniques used
Steps taken to fix the issue
Verification of the solution
Impact of the fix

Possible Follow-up Questions

What made this issue particularly difficult to detect?
How did you systematically approach the debugging process?
How did you ensure the fix wouldn't cause other problems?
What preventive measures did you implement to avoid similar issues?

Give me an example of how you've kept up with changes in iOS development over the past few years and applied new knowledge to your work. (Continuous Learning)

Areas to Cover

Learning methods and resources used
Specific new technologies or patterns learned
Evaluation process for new approaches
Application of new knowledge in projects
Challenges faced during implementation
Results of applying new knowledge
How they share learning with team members

Possible Follow-up Questions

How do you prioritize what new technologies to learn?
What's your approach when learning something that's outside your comfort zone?
How have you helped your team adopt new iOS technologies?
Can you share an example where learning something new significantly improved your work?

Describe a situation where you had to push back on a requested feature or implementation approach because it would compromise the quality or performance of the iOS app. (Technical Problem-Solving, Communication)

Areas to Cover

Context of the situation and requested feature
Technical concerns identified
How they analyzed the potential impact
How they communicated their concerns
Alternative solutions proposed
Reaction from stakeholders
Final outcome and lessons learned

Possible Follow-up Questions

How did you balance being collaborative while standing firm on technical concerns?
How did you explain technical issues to non-technical stakeholders?
What data or evidence did you use to support your position?
How was your relationship with the stakeholders after this interaction?

Tell me about a complex iOS project you worked on. How did you organize your work and ensure you delivered high-quality code on schedule? (Attention to Detail, Technical Problem-Solving)

Areas to Cover

Project scope and complexity
Planning and organization approach
Time management strategies
Quality assurance processes used
Challenges encountered and solutions
Collaboration with team members
Project outcome and lessons learned

Possible Follow-up Questions

How did you break down the complex project into manageable tasks?
What tools or methods did you use to track progress?
How did you handle unexpected issues that threatened the timeline?
What quality checks did you build into your development process?

Interview Scorecard

Collaboration and Communication

0: Not Enough Information Gathered to Evaluate
1: Struggles to collaborate effectively or communicate clearly
2: Adequate collaboration skills but room for improvement
3: Strong collaborator who communicates effectively
4: Exceptional ability to collaborate and communicate across diverse teams

Adaptability

0: Not Enough Information Gathered to Evaluate
1: Resistant to change or slow to adapt
2: Can adapt to change but may require significant support
3: Adapts well to changing priorities and requirements
4: Thrives in changing environments and helps others adapt

Attention to Detail

0: Not Enough Information Gathered to Evaluate
1: Often misses important details
2: Catches obvious issues but may miss subtle problems
3: Demonstrates good attention to detail in most situations
4: Exceptional thoroughness and precision in all work

Continuous Learning

0: Not Enough Information Gathered to Evaluate
1: Limited interest in learning new technologies
2: Learns when required but not proactively
3: Consistently seeks to learn and apply new knowledge
4: Passionate learner who drives technical advancement

Technical Problem-Solving

0: Not Enough Information Gathered to Evaluate
1: Struggles with complex technical challenges
2: Solves routine problems but may need help with complex issues
3: Strong problem-solver who can tackle most technical challenges
4: Exceptional problem-solving abilities with innovative approaches

Develop and maintain high-quality iOS applications

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on attention to detail
2: Likely to Partially Achieve Goal with oversight
3: Likely to Achieve Goal with demonstrated quality focus
4: Likely to Exceed Goal with exceptional quality standards

Collaborate effectively with cross-functional teams

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on communication approach
2: Likely to Partially Achieve Goal with some skill gaps
3: Likely to Achieve Goal with good collaboration skills
4: Likely to Exceed Goal with outstanding team interaction

Reduce bug counts and technical debt

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on quality approach
2: Likely to Partially Achieve Goal with supervision
3: Likely to Achieve Goal with good attention to detail
4: Likely to Exceed Goal with proactive quality improvement

Stay current with iOS platform changes

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on learning habits
2: Likely to Partially Achieve Goal with prompting
3: Likely to Achieve Goal with demonstrated learning
4: Likely to Exceed Goal with exceptional learning drive

Overall Recommendation

1: Strong No Hire - Significant concerns with behavioral competencies
2: No Hire - Behavioral competencies don't align with our needs
3: Hire - Strong behavioral competencies that fit our team
4: Strong Hire - Exceptional behavioral competencies

Debrief Meeting

Directions for Conducting the Debrief Meeting

The Debrief Meeting is an open discussion for the hiring team members to share the information learned during the candidate interviews. Use the questions below to guide the discussion.

Start the meeting by reviewing the requirements for the role and the key competencies and goals to succeed as an iOS Developer at [Company].

The meeting leader should strive to create an environment where it is okay to express opinions about the candidate that differ from the consensus or from leadership's opinions.

Scores and interview notes are important data points but should not be the sole factor in making the final decision.

Any hiring team member should feel free to change their recommendation as they learn new information and reflect on what they've learned.

Questions to Guide the Debrief Meeting

Does anyone have any questions for the other interviewers about the candidate?

Guidance: The meeting facilitator should initially present themselves as neutral and try not to sway the conversation before others have a chance to speak up.

Are there any additional comments about the Candidate?

Guidance: This is an opportunity for all the interviewers to share anything they learned that is important for the other interviewers to know.

Is there anything further we need to investigate before making a decision?

Guidance: Based on this discussion, you may decide to probe further on certain issues with the candidate or explore specific issues in the reference calls.

Has anyone changed their hire/no-hire recommendation?

Guidance: This is an opportunity for the interviewers to change their recommendation from the new information they learned in this meeting.

If the consensus is no hire, should the candidate be considered for other roles? If so, what roles?

Guidance: Discuss whether engaging with the candidate about a different role would be worthwhile.

What are the next steps?

Guidance: If there is no consensus, follow the process for that situation (e.g., it is the hiring manager's decision). Further investigation may be needed before making the decision. If there is a consensus on hiring, reference checks could be the next step.

Reference Checks

Directions for Conducting Reference Checks

Reference checks are a crucial step in validating the candidate's experience and competencies. They provide independent perspectives on the candidate's work style, technical skills, and behavioral traits. Focus on gathering specific examples rather than general impressions.

Contact at least two professional references who worked directly with the candidate, ideally including a former manager and a colleague. Encourage the candidate to prepare their references by letting them know you'll be calling and what types of questions you'll ask.

Conduct the reference checks by phone rather than email to allow for a more natural conversation and the ability to ask follow-up questions. Take detailed notes during the conversation.

This reference check template can be used multiple times with different references for the same candidate. Compare insights across references to identify patterns and consistency.

Questions for Reference Checks

In what capacity did you work with [Candidate] and for how long?

Guidance: Establish the reference's relationship with the candidate and the context of their work together. Determine if they worked together directly and recently enough to provide relevant insights.

What were [Candidate]'s primary responsibilities as an iOS Developer on your team?

Guidance: Verify that the candidate's description of their role matches what the reference describes. Listen for specifics about the projects they worked on and their level of responsibility.

How would you rate [Candidate]'s technical skills, particularly in iOS development? Can you provide specific examples of complex problems they solved?

Guidance: Look for concrete examples that demonstrate the depth of the candidate's technical abilities. Ask follow-up questions about specific frameworks or challenges mentioned in the candidate's interview.

Tell me about [Candidate]'s ability to collaborate with cross-functional teams, including designers and product managers.

Guidance: Communication and collaboration are critical for this role. Listen for how the candidate navigated different perspectives and communicated technical concepts to non-technical team members.

How does [Candidate] handle changes in priorities or requirements? Can you share an example?

Guidance: Adaptability is important in fast-paced development environments. Look for evidence of flexibility and a positive approach to change.

What would you say are [Candidate]'s greatest strengths and areas for growth?

Guidance: This question often reveals nuanced insights about the candidate. Pay attention to whether the areas for growth would be problematic in your environment or if they're areas your team could help develop.

On a scale of 1-10, how likely would you be to hire [Candidate] again if you had an appropriate role, and why?

Guidance: This direct question often elicits honest feedback. The explanation is as important as the numerical rating. A rating below 8 warrants further exploration.

Reference Check Scorecard

Technical Proficiency

0: Not Enough Information Gathered to Evaluate
1: Reference indicates significant technical limitations
2: Reference suggests adequate but not exceptional technical skills
3: Reference confirms strong technical capabilities
4: Reference highlights exceptional technical expertise with specific examples

Collaboration Skills

0: Not Enough Information Gathered to Evaluate
1: Reference notes challenges working with others
2: Reference indicates adequate but inconsistent collaboration
3: Reference confirms effective collaboration across teams
4: Reference highlights exceptional ability to build relationships and work across functions

Adaptability

0: Not Enough Information Gathered to Evaluate
1: Reference suggests resistance to change
2: Reference indicates can adapt but may struggle with major changes
3: Reference confirms good adaptability to changing conditions
4: Reference highlights exceptional ability to thrive amid change and uncertainty

Quality and Attention to Detail

0: Not Enough Information Gathered to Evaluate
1: Reference notes issues with code quality or thoroughness
2: Reference suggests adequate but inconsistent attention to detail
3: Reference confirms consistent quality and thoroughness
4: Reference highlights exceptional commitment to excellence and precision

Develop and maintain high-quality iOS applications

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on reference feedback
2: Likely to Partially Achieve Goal with supervision
3: Likely to Achieve Goal with confirmed capabilities
4: Likely to Exceed Goal with exceptional past performance

Contribute to technical architecture and design decisions

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on limited past contributions
2: Likely to Partially Achieve Goal with some experience
3: Likely to Achieve Goal with confirmed design experience
4: Likely to Exceed Goal with exceptional architectural contributions

Reduce bug counts and technical debt

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on quality history
2: Likely to Partially Achieve Goal with oversight
3: Likely to Achieve Goal with good quality practices
4: Likely to Exceed Goal with outstanding quality focus

Collaborate effectively with cross-functional teams

0: Not Enough Information Gathered to Evaluate
1: Unlikely to Achieve Goal based on collaboration history
2: Likely to Partially Achieve Goal with some improvement
3: Likely to Achieve Goal with good collaboration skills
4: Likely to Exceed Goal with excellent team interactions

Frequently Asked Questions

How should I prioritize technical skills versus behavioral competencies when evaluating iOS Developer candidates?

Both are important, but the balance depends on your team's needs. Technical skills are foundational – the candidate must have strong iOS development capabilities to succeed. However, behavioral competencies like collaboration and continuous learning often determine long-term success and team fit. A candidate with moderate technical skills but exceptional behavioral competencies may grow into a stronger contributor than someone with excellent technical skills but poor collaboration abilities.

What if a candidate doesn't have experience with a specific framework or technology we use?

Focus on their core iOS development skills and learning agility rather than specific technology experience. Strong iOS developers can quickly learn new frameworks if they have solid fundamentals. During the interview, ask how they've learned new technologies in the past and assess their understanding of similar concepts. You might also consider giving them a small learning exercise to evaluate how quickly they can pick up new technologies.

How can I effectively evaluate a candidate's code quality through the interview process?

The coding exercise is your best opportunity to assess code quality directly. Look for clear organization, appropriate design patterns, error handling, and documentation. During technical discussions, ask candidates about their approach to code reviews and quality assurance. You can also ask about specific quality challenges they've faced and how they addressed them. For more guidance, see our blog post on conducting technical interviews.

Should we give candidates feedback on their coding exercise?

Providing brief, constructive feedback on coding exercises can improve your candidate experience and employer brand, even for candidates you don't hire. However, keep feedback focused on 1-2 key areas rather than an exhaustive review. For candidates you're advancing, discussing their code during the technical interview provides valuable insight into how they respond to feedback, which is an important skill for any developer.

How do we ensure we're evaluating candidates consistently across different interviewers?

This interview guide is designed to create consistency, but you should also hold a brief calibration session with all interviewers before beginning the process. Review the scorecard criteria together to ensure shared understanding. After the first few candidates, check if interviewers are applying standards consistently. Having overlapping competencies assessed by different interviewers can also help identify and address inconsistencies in evaluation.