Mobile System Design

By the author of the Mobile System Design and Swift in Depth books
Tjeerd in 't Veen

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Tjeerd in 't Veen

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How to Prepare for a Mobile System Design Interview

Wed, 4 Jun 2025, reading time: 4 minutes

Preparing for a mobile system design interview feels like wandering into a backend-heavy maze.

Most resources (such as books, cheat sheets or YouTube videos) talk about backend specific system design topics; load balancers, redis, and servers in multiple regions.

That’s great information, sure. But not exactly what you’ll face when asked how to sync offline edits or build a photo uploader that works in the background.

You’re more likely to get questions related to building features for a local architecture. Such as how to design a feed for a social media app, or a feature flag system (to remotely enable and disable parts of features), or how to ensure a feature can work without an internet connection.

Mobile challenges are very different, and often focused on UI in combination with local architectures. After all, you’re shipping a single binary (app), which comes with more challenges related to a local codebase, shared with others.

Preparing for a mobile system design interview doesn’t have to mean studying backend infrastructure. Here’s how to prepare efficiently with mobile-focused examples and tools.

Resources

Short on time?

Read the free Mobile System Design Interview Guide (~15 min)
This guide shows you what to expect during an interview. So you aren’t going in blind.

Prepare using the Mobile System Design Interview Cheat Sheet (40 pages, part of paid Book Bundle)
This is the fastest, most focused prep available. It shows you how to get hidden requirements, contains printable checklists, how to design component API’s, and has diagram walkthroughs.

It’s part of the book bundle, so when you purchase this guide to get that job, you have the books to further grow your career.

Have more time?

Not all problems can be pre-rehearsed on a diagram-level. You can't only rely on use cases either. It's about deeply understanding the problem you're solving.

Therefore, I recommend getting comfortable building things you don't yet know how to build. That’s what led me to write the Mobile System Design book and the Mobile System Design Interview Cheat Sheet.
Tjeerd in 't Veen
— Tjeerd in ’t Veen
Author of Mobile System Design
Former Staff Engineer at Twitter, Mobile Tech Lead at ING

Good luck!

Interviewing can be stressful and unpredictable.

Luckily, the system design interviews can be the most fun of all of them. A good interview can feel like a collaborative whiteboard session, or even a bit like pair programming.

The Mobile System Design book bundle

Want to level up your architecture skills or prepare for tough system design interviews? The Mobile System Design book bundle gives you practical tools and real-world insights to help you grow as a mobile engineer.

It includes the Quick Reference Cheat Sheet to help you land the job, and the full books to help you thrive in it.

Mobile System Design Book Collection

Trusted by engineers at Facebook, New York Times, and more!

I am the author of these books, but you may also know me from the highly-rated Swift in Depth book.

Even if you're a senior or staff-level engineer, I am confident you'll get a lot out of it.

It covers topics in depth such as:

  • Tackle system design interviews with confidence
  • Scale apps and teams without sacrificing speed
  • Avoid over-engineering with practical patterns
  • Use dependency injection without the framework bloat
  • Deliver features faster with fewer mistakes
  • Seamlessly integrate design systems into real-world apps

... and much more!

Get the Mobile System Design book bundle

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Written by

Tjeerd in 't Veen has a background in product development inside startups, agencies, and enterprises. His roles included being a staff engineer at Twitter (before X) and iOS Tech Lead at ING Bank.

He is the author of the Mobile System Design and Swift in Depth books.