OpenAI — Mobile Engineer ❌ Failed
Level: Senior-Level
Round: Onsite · Type: Multiple Types · Difficulty: 6/10 · Duration: 360 min · Interviewer: Unfriendly
Topics: iOS, UI, UIKit, SwiftUI, System Design, Chat Application, Refactoring, Behavioral Questions
Location: San Francisco Bay Area
Interview date: 2026-01-22
Got offer: False
Summary
Round 1: Phone Screen (Coding)
Question: Implement UI features in a sample iOS project using either UIKit or SwiftUI. I used UIKit and felt disadvantaged.
Round 2: Phone Screen (System Design)
Question: Design a chat application similar to WhatsApp with standard features.
Round 3: Onsite (Coding)
Question: Refactor a chatbot.
Round 4: Onsite (Project Deep Dive)
Question: Deep dive into previous projects.
Round 5: Onsite (Behavioral)
Question: General behavioral questions.
Round 6: Follow-up Coding
Question: Coding problem. I solved it quickly without bugs.
Details
Preparation Tips & Key Takeaways
What I Learned
- I should have used SwiftUI instead of UIKit for the iOS coding challenge.
- System design questions for chat applications are common and should be prepared for.
Recommended Preparation
Coding Practice
- Practice iOS UI development with SwiftUI.
- Focus on refactoring coding problems.
System Design
- Study common system design patterns for chat applications.
- Review requirements for designing real-time applications.
Behavioral Questions
- Prepare STAR stories for project deep dives.
- Practice discussing technical challenges and solutions.
Resources I Recommend
- Apple's SwiftUI documentation.
- System design resources focused on real-time applications.
Common Pitfalls to Avoid
- Choosing UIKit over SwiftUI may be perceived negatively.
- Neglecting to prepare for system design questions.