They are not scoring your answer. They are scoring which level it came from.
182 iOS interview questions, each answered three times: what most candidates say, what a senior says, and what a staff+ engineer says.
Built from more than 500 technical interviews on the hiring side, with the red flags that weaken answers and the follow-up questions that reveal whether the depth is real.
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Updated · 8 August 2026
182worked interview questions
3×answer depth on core topics
230pages · PDF and EPUB
500+interviews behind the material
What the book actually does
One question. Three altitudes.
This is the difference the book trains you to hear: correctness, senior judgment, and the systems view behind the answer.
Q An actor guards your cart. Where does that break?
What most candidates say
An actor serialises access to its state, so two tasks never touch it at the same instant and you cannot have a data race. Correct, complete, and worth no extra credit.
What a senior candidate says
An actor releases at every await. Read the cart, await the save, write it back, and a second task can enter during the suspension, read the same value and write first. Your write lands last and wins. Two correct operations, one destroyed record, and no data race at any instant.
What a staff+ candidate says
The compiler proved there was no data race and the proof was accurate. What it cannot know is what your state is supposed to mean between two lines of your own function. That is a semantic invariant. The fix is rechecking state after suspension, making the operation idempotent, or removing the shared reference entirely.
Same topic. Different signal. The interviewer is deciding which altitude you operate at, and the follow-up is usually where that becomes obvious.
Red flags, quoted
“Use unowned because it is faster or avoids the optional.” Cargo cult, and a crash waiting on a lifetime you never verified.
Calling ARC garbage collection, or saying it runs periodically.
“I would just read the code to find the leak.” Senior engineers reach for the Memory Graph Debugger.
The follow-up they ask next
“You marked it unowned. What happens if the parent deallocates first?” A crash. Can you defend the lifetime guarantee?
“Does weak self solve every closure leak?” No. A strongly captured local can still cycle.
“How would you prove this leaks in CI?” A deinit expectation test, or XCTMemoryMetric.
The preparation system
Know the answer. Then know what happens after it.
01 · Answer depth
Hear the gap between correct and senior.
Core questions are shown at multiple levels so you can practice the depth, trade-offs, and production reasoning the interviewer is actually listening for.
02 · Red flags
Remove phrases that quietly cost points.
Interview damage is often subtle: terminology that signals cargo-cult knowledge, assumptions you cannot defend, or fixes that ignore the real failure mode.
03 · Follow-ups
Prepare for the second question.
The first answer opens the door. The follow-up tests whether you can defend constraints, failure modes, alternatives, and consequences under pressure.
Verified purchases
What readers wrote after using it.
★★★★★
“I used to fail technical interviews constantly, despite watching countless online courses. Then I found Mike's book on LinkedIn, and it made all the difference. After six months of searching and over ten failed interviews, his plan worked for me, leading to my first job contract today.”
★★★★★
“The sections on modularization, Swift internals, architecture trade-offs and system design felt much closer to real senior-level interviews than anything else I've read.”
★★★★★
“Every explanation of different answer levels helped me understand the gap between a correct answer and a strong senior-level answer.”
★★★★★
“I love this book. It's become my go-to starting point whenever I'm preparing for iOS interviews. Clear, practical, and packed with valuable insights.”
★★★★★
“Very good for interview preparation, from junior to lead. Recommended.”
What is inside
Nine chapters, mapped to the level of the room.
Start at your target role, then read one level above it to hear how the expected depth changes.
Chapter 1 · Junior
Swift fundamentals, UIKit lifecycle, networking, Codable, memory management and ARC.
Chapter 2 · Mid level
Property wrappers, Swift concurrency, SwiftUI, modern architectures, testing, dependency injection, Core Data and SwiftData.
Chapter 3 · Senior
Modular design, The Composable Architecture, advanced persistence, security, CI/CD, the SwiftUI rendering pipeline and Swift internals.
Chapter 4 · Senior in transition
Mentorship, cross-functional work, behavioral answers with engineering specifics, promotion narratives and negotiating level.
Chapter 5 · Tech lead
Mobile system design, technical direction, roadmap planning and system-design walkthroughs.
Chapter 6 · Mobile architect
Multi-platform strategy, modularization at scale, architecture governance, on-device AI and release architecture.
Chapter 7 · Engineering manager
What an EM loop measures, round by round, team topology and owning the release train.
Chapter 8 · Delivery
Planning for a binary you cannot take back.
Chapter 9 · The live round
Live coding method, take-home strategy and how AI assistance is treated in a modern loop.
Fit
This is for engineers with a real loop to prepare for.
Good fit
iOS engineers with a real interview loop coming up
Mid-level engineers who want to hear what senior sounds like before being asked to be it
Engineers who pass screens and stall at onsite or system design
Tech leads, architects and engineering managers preparing for scope questions rather than syntax
Interviewers who want sharper follow-up questions
Not the right fit
You are learning iOS from zero
You want definitions to memorise without trade-offs
You are not preparing for a real interview loop
Written from the hiring side
Mike Salari
Staff Mobile Engineer · Tech Lead · Technical Author
Fifteen years building production mobile systems, much of it in fintech, where being wrong is expensive. Somewhere in the middle of that I ended up on the hiring side: screening calls, technical rounds, live coding, system design and debriefs. More than five hundred and counting.
The point of the book is not another list of definitions. It is the hiring-side scorecard you normally never see.
Before you buy
Read the real sample first.
The free 25-page PDF sample lets you inspect the writing, question depth, and career-leveled structure before spending anything.
No. The chapters run from junior through mid level, senior, senior in transition, tech lead, mobile architect, engineering manager and delivery. Each answer shows what the level above sounds like, which is the point.
How is this different from a list of interview questions?
A list gives you the correct answer. This gives you the same question at three altitudes, the phrases that quietly damage a candidate, and the follow-up an interviewer asks next, so you prepare for the second question rather than only the first.
Is it current?
This revision is checked against Swift 6.2 and the iOS 26 SDK. Anything still moving is labelled rather than presented as settled, and future editions are included with purchase.
Does it cover system design and behavioral rounds?
Yes. Mobile system design has its own material at tech lead and architect level, behavioral material uses the same answer structure, and Chapter 9 covers the live coding round and take-homes.
What formats do I get, and how is it delivered?
PDF and EPUB, delivered instantly through Gumroad. Future editions are included.
What if it is not for me?
Reply to your Gumroad receipt within 14 days for a full refund.
Go into the room with a structure
Prepare for the second question, not the first.
182 questions, three answer levels on the topics that decide seniority, from the side of the table that scores you.
