Mastering the System’s Design Interview: Asking the Right Questions

Mastering the System’s Design Interview: Asking the Right Questions (Part 1)

By Frank Kane

This article is an excerpt from our Mastering the System’s Design Interview course. In this section, we will dive into the key questions you should ask during your interview to help you stand out from the crowd.

When it comes to an interview, your ability to navigate the interview is just as important as your skills and credentials. 

Your potential employer is not only evaluating your technical expertise but also how you approach problems in general and how you work with others. That is equally important to the technology that you’re invoking. 

So, let’s discuss strategies for getting through the interview itself successfully. These are more about soft skills and how you approach problems than the actual technologies themselves. As an interviewer at Amazon, where I did thousands of these interviews, this is what I’m looking for more than anything else. 

I want you to come up with a solution that makes sense, but it’s less important to me that you finish and describe a fully fleshed-out system that scales. I’m more interested in whether you can take feedback from me. 

  • How do you respond to my direction? 
  • How well do you work with me?
  • How do you think? 
  • How do you approach problems?

Usually, in a system design interview question, you’re going to be given some incredibly vague problem to solve – and that is intentional. The interviewer wants you to break that down and clarify the requirements of what you’re asking them to build. 

I might give you some incredibly high-level things, like “design YouTube for me”, or “design Google search please”. Some people will just sit there and look like a deer in headlights and quietly cry to themselves a little bit (they don’t really, at least I hope not). 

The successful interviewee will say, “Okay, let’s break that down and see what you really want me to do.” The first step is to turn this vague direction they’ve given you into concrete requirements. 

  1. Always start by repeating the question. That’s just a basic communication skill. If someone’s asking you to do something, just to repeat it back to them and make sure that you understand it properly. 

So, if I say, “design YouTube”, the first thing you should say is, “okay, you want me to design YouTube, you know, the big video streaming service” and make sure you’re on the same page. 

2. Now, it’s time to ask lots of questions. 

  • Break that down into what they really want you to build.
  • Clarify what the requirements for it are. 
  • Think out loud. 

3. As you approach a problem, don’t just sit there in silence. That’s not doing you any good. Let your interviewer see your thought process. 

As you’re thinking about different strategies and the pros and cons of them, don’t keep it inside your head where the interviewer can’t see it. Talk about it as you’re thinking through it. That will give the interviewer a chance to steer you in the right direction, which is going to help you. 

Learn more strategies on how to Master your System Design Interview today with our Mastering the Systems Design Interview Course. Click here to enroll today.

Stay tuned for part two of this series, coming soon.

Published by

Frank Kane

Frank spent 9 years at Amazon and IMDb, developing and managing the technology that automatically delivers product and movie recommendations to hundreds of millions of customers, all the time. Frank holds 17 issued patents in the fields of distributed computing, data mining, and machine learning. In 2012, Frank left to start his own successful company, Sundog Software, which focuses on virtual reality environment technology, and teaching others about big data analysis.

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