The Ultimate iOS Interview Question Bank for Swift Developers — Part 1

The Basics, Operators, Strings, Collections, Control Flow, Functions & Closures

Modern iOS interviews evaluate far more than syntax knowledge.

Companies today expect iOS engineers to understand:

• Swift language fundamentals
• Memory behavior
• API design
• Functional programming
• Thread safety
• Performance implications
• Readability and maintainability
• Swift runtime behavior
• Modern Swift concurrency concepts

This interview series follows a structure inspired by the Swift Official Documentation so developers can systematically prepare for interviews instead of memorizing disconnected questions.

This part focuses on:

• The Basics
• Basic Operators
• Strings & Characters
• Collection Types
• Control Flow
• Functions
• Closures

Questions are grouped into:

• Must Know Questions — Frequently asked in Mid-Level and Senior iOS interviews
• Advanced Questions — Common in Senior, Lead, Staff, and Principal Engineer interviews