2026

iOS Interview Questions 2026

A current, 2026 snapshot of the iOS interview questions worth knowing — kept up to date as frameworks and best practices evolve, so you prepare with what companies are actually asking in 2026.

99Questions14Beginner13Intermediate72Senior

99 iOS questions

  1. 1What is MVVM architecture?Intermediate
  2. 2What are notifications in iOS?Intermediate
  3. 3Weak vs Unowned referencesIntermediate
  4. 4What is SwiftUI?Intermediate
  5. 5What is URLSession in iOS?Intermediate
  6. 6What is Codable in Swift?Intermediate
  7. 7How does error handling work in Swift?Intermediate
  8. 8What are extensions in Swift?Intermediate
  9. 9What are protocols in Swift?Intermediate
  10. 10What are closures in Swift?Intermediate
  11. 11What is Grand Central Dispatch (GCD)?Beginner
  12. 12What is UITableView?Beginner
  13. 13What is delegation pattern in iOS?Beginner
  14. 14What are IBOutlets and IBActions?Beginner
  15. 15What is UIViewController lifecycle?Beginner
  16. 16What is ARC in iOS?Beginner
  17. 17Class vs Struct in SwiftBeginner
  18. 18Difference between arrays and dictionaries in SwiftBeginner
  19. 19What are optionals in Swift?Beginner
  20. 20What are variables in Swift (let vs var)?Beginner
  21. 21iOS Interview Question 5 (Free)Intermediate
  22. 22iOS Interview Question 4 (Free)Beginner
  23. 23iOS Interview Question 3 (Free)Senior
  24. 24iOS Interview Question 1 (Free)Beginner
  25. 25iOS Interview Question 2 (Free)Intermediate
  26. 26How do you design testable architecture in iOS at enterprise scale?Senior
  27. 27How do you design a scalable deep linking architecture in iOS?Senior
  28. 28How do you design a multi-layer data flow architecture in iOS?Senior
  29. 29How do you design a resilient networking architecture with retries, circuit breakers, and fallbacks?Senior
  30. 30How do you design a domain-driven architecture in iOS?Senior
  31. 31How do you design a plugin-based feature toggle system in iOS architecture?Senior
  32. 32How do you design a scalable caching architecture for offline-first iOS apps?Senior
  33. 33What is state machine architecture in iOS and when should you use it?Senior
  34. 34How do you design a reactive architecture in iOS using Combine at scale?Senior
  35. 35How do you scale iOS architecture across multiple teams (monorepo strategy)?Senior
  36. 36How do you design persistence architecture in iOS applications?Senior
  37. 37How should networking architecture be designed in iOS apps?Senior
  38. 38How do you design navigation architecture in large iOS apps?Senior
  39. 39What is plugin-based architecture in iOS?Senior
  40. 40How does offline-first architecture work in iOS apps?Senior
  41. 41What is CQRS architecture and how can it be applied in mobile apps?Senior
  42. 42How do you design event-driven architecture in iOS apps?Senior
  43. 43What is Hexagonal Architecture (Ports and Adapters) in iOS?Senior
  44. 44How does The Composable Architecture (TCA) work in large iOS apps?Senior
  45. 45How do you handle cross-feature communication in modular iOS apps?Senior
  46. 46What is caching architecture in iOS apps?Senior
  47. 47How does unidirectional data flow architecture work in iOS?Senior
  48. 48What is feature modularization in iOS architecture?Senior
  49. 49How do you design dependency injection at scale in iOS apps?Senior
  50. 50What is the Repository pattern in iOS architecture?Senior
  51. 51How do you manage state in large-scale iOS applications?Senior
  52. 52What is Clean Architecture in iOS and how do you implement it at scale?Senior
  53. 53Explain MVVM-C architecture and why it is used in large iOS appsSenior
  54. 54How do you design a scalable iOS architecture for large applications?Senior
  55. 55Advanced debugging techniques in iOS (LLDB and Instruments)Senior
  56. 56How to design modular iOS applications?Senior
  57. 57What causes deadlocks in iOS threading?Senior
  58. 58How does Core Animation improve performance?Senior
  59. 59What is SSL pinning in iOS?Senior
  60. 60How does Objective-C interoperability work in Swift?Senior
  61. 61What is Swift runtime and reflection?Senior
  62. 62What is RunLoop in iOS?Senior
  63. 63What is Clean Architecture in iOS?Senior
  64. 64What are SOLID principles in iOS development?Senior
  65. 65How to improve iOS app startup performance?Senior
  66. 66What is Swift Package Manager (SPM)?Senior
  67. 67What is a dependency injection container?Senior
  68. 68What is the Coordinator pattern in iOS?Senior
  69. 69What are Universal Links in iOS?Senior
  70. 70How does background processing work in iOS?Senior
  71. 71How to optimize UITableView and UICollectionView performance?Senior
  72. 72How does ARC lead to retain cycles?Senior
  73. 73What is TaskGroup in Swift concurrency?Senior
  74. 74What is backpressure in Combine?Senior
  75. 75How to debug crashes in iOS apps?Senior
  76. 76How to scale iOS apps for large teams?Senior
  77. 77What is API pagination?Senior
  78. 78How to secure iOS apps?Senior
  79. 79What is Keychain in iOS?Senior
  80. 80How do push notifications work?Senior
  81. 81What is code signing in iOS?Senior
  82. 82What is snapshot testing?Senior
  83. 83What is unit testing in iOS?Senior
  84. 84What is CI/CD in iOS development?Senior
  85. 85How to handle race conditions in iOS?Senior
  86. 86What is Core Data concurrency?Senior
  87. 87What is diffable data source?Senior
  88. 88What are Instruments in Xcode?Senior
  89. 89How to detect memory leaks in iOS?Senior
  90. 90What is Combine framework?Senior
  91. 91What are actors in Swift?Senior
  92. 92Explain async/await in SwiftSenior
  93. 93What is dependency injection in iOS?Senior
  94. 94What is MVC architecture in iOS?Senior
  95. 95iOS Advanced Interview Question 10Beginner
  96. 96iOS Advanced Interview Question 9Senior
  97. 97iOS Advanced Interview Question 8Intermediate
  98. 98iOS Advanced Interview Question 7Beginner
  99. 99iOS Advanced Interview Question 6Senior

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Frequently asked questions

Are these iOS interview questions up to date for 2026?

Yes. This page reflects 99 iOS interview questions kept current with today's frameworks, tooling and interview trends, with each answer maintained and dated.

What iOS topics should I focus on in 2026?

Prioritise the fundamentals plus the modern patterns interviewers ask about now. Each question here includes a detailed answer, code example and common mistakes so you can target the highest-impact areas.

Are these questions free?

You can read the question and a short answer for free. A subscription unlocks the full detailed explanation, real-world example, common mistakes and follow-up questions for each one.