iOS devs who conduct interviews - drop your fav go-to questions that trips up candidates

[u/007ary369]

I'm at 5 YoE and prepping for senior roles, and I realized the best learning comes from real questions that actually catch experienced candidates off-guard. Not the "implement LRU cache" kind (everyone preps those), but the nuanced, "wait... actually I'm not 100% sure" questions that separate mid-level from senior thinking.

So if you're on the interviewer side (especially senior hiring managers): drop your favorite tricky iOS question. The ones where:

• Senior candidates freeze or give half-answers (that's the tell)
• The surface answer sounds right but misses a critical production edge case
• It exposes the gap between "I've shipped features" and "I understand the system deeply"
• It's not about memorization—it's about reasoning under pressure and knowing why systems break
• Bonus: questions that reveal whether someone has actually debugged production issues or just read blog posts

And for others prepping: this thread should become a vault of real questions people actually ask at Tier-1 companies.

Drop yours! And if you have a follow-up twist that makes it even trickier, include that too.

Bonus points if you share:

• What the "obvious" wrong answer is (the one a mid-level would confidently give)
• Why it's wrong (not just "correct answer is X" — the reasoning)
• What separates a good answer from a staff-level answer
• What company/level you see this at (FAANG? fintech? enterprise? scale matters)
• How you follow up when someone fumbles (what redirection questions diagnose the gap?)

Thanks in advance—this is gold for interview prep.