My iOS Interviews Preparation

Recently, I landed two generous job offers from two great companies. Friends in the industry complimented me on this nontrivial achievement, as the job market was considered relatively weak. So, I decided to put my experience into writing to hopefully help others.

In this post, I'll focus on three key technical aspects of the iOS interviews:

1. General iOS Knowledge

2. Mobile System Design

3. Home Assignment / Live Coding Session Preparation

4. Optional Bonus: LeetCode-Type Questions

General iOS Knowledge

I like reading books on iOS and Software Development in general. However, for iOS interview preparation, you need only one book: "The Ultimate iOS Interview Playbook" by Avi Tsadok. This book is the best resource for covering broadly and deeply everything you need to know about iOS. It prepares you to answer questions confidently and engage in in-depth conversations about iOS.

Mobile System Design

Resources for mobile system design preparation are scarce, with most focusing on back-end system design. During this interview round, I discovered Andrey Tech's top-notch YouTube channel. This is pretty fresh material that wasn't around in my previous round. Andrey takes common system design requirements and dissects them in a whiteboard style. His videos are short, well-structured, and incredibly insightful. When I produced similar diagrams during interviews, the interviewers were very impressed.

Home Assignment/Live Coding Preparation

In 90% of iOS interviews, there is a home assignment or live coding session. Typically, the task involves presenting a list of items fetched from the internet and a detailed screen. Knowing this, I created such an app in advance, which proved to be incredibly beneficial.

I spent a few weeks working on this app, reading blogs on good architectures, using the latest APIs, adding tests, and even modularizing the app (the modularization part is unnecessary extra). I discussed and reviewed the code with several senior friends, received feedback, and made improvements. Having it as a reference, I could recreate a similar one in no time.

For the interviewers, it was impressive to witness a well-structured app assembled quickly, but this was the result of weeks of preparation. I feel a bit like a magician revealing a trick 😄

* you should try to develop this app without third-party libraries, as it is often a requirement.

You can find the app here.

Bonus: LeetCode-Style Questions

The final part of the interview process involves LeetCode-style questions, a section many developers dread due to the significant time and effort required to prepare for this part. Frankly, if you excel in the previous parts, delivering a subpar performance here can still land you an offer.

LeetCode's design can be somewhat daunting, so I recommend an alternative suggested to me by a Meta recruitment team: InterviewCake.com. To truly nail the interview, start working on these questions 2-3 months before beginning the interview process. Aim to tackle a question every other day, which will take around 20-40 minutes.

I didn't practice them this time, but I was asked and managed to answer them satisfactorily. It’s like riding a bike; the skills come back to you. This is a great cherry on top of your interview preparation.

Securing two job offers in a challenging market was a rewarding experience, and I hope my journey can provide valuable insights for others navigating the iOS interview process.

Good luck!