The Secret to Nailing Your System Design Interview
By Frank Kane
This article is an excerpt from our course, Mastering the System Design Interview. We hope you find these tips useful in your next interview.
So what is the secret to nailing your system design interview? Well, it might be simpler than you think. One of the top ways to nail your System Design Interview is to simply THINK OUT LOUD!
Yes, you read that right: think out loud during your interview. Don’t just clam up for 10 minutes while you think about things. For all you know, you only have 15 minutes for this question, and you don’t want to spend 10 minutes of it just sitting there in silence while your interviewer wonders what you’re thinking. Do yourself a favor, and do NOT do that.
Think out loud. Use that time to clarify requirements, define the constraints of what you need to build, and then think out loud about the high-level solutions you’re considering to meet those requirements. Say what you’re thinking. “Okay, well, I think we need a CDN, and maybe we need to use Apache Spark to process the data down here, and maybe Kinesis to stream stuff over here, and maybe DynamoDB over here to store that data.” Just talk and think, and let the interviewer see how you’re approaching this problem from a technical standpoint.
Thinking out loud is important because it gives the interviewer not only a chance to see how you think but also to steer you in the right direction and see how you respond to that guidance. Part of what they’re trying to evaluate is what it will be like to work with you every single day. So, work with them. Show that you can work with them. Think out loud. Let them work collaboratively with you. Show that you can take feedback. Show that you can modify your design in response to that feedback, and not get defensive about it. That’s a much better use of that 10 minutes than just sitting there in silence.
Again, you don’t know how much time you have for a given system design problem. Very often, it’s only about 20 minutes. If you spend half of it just sitting there in silence, you’ve wasted that time. You’ve wasted that opportunity to show your interviewer how you think.
So here’s the key takeaways:
- Don’t just clam up for 10 mins while you think about things.
- Clarify requirements, and define the constraints of what you need to build.
- Think out loud about the solutions you’re considering to meet those requirements.
- Give the interviewer a chance to steer you in a different direction before you start diving into details.
- You don’t know how much time you have for this part of the interview, so make every minute count.
If you’re interested in learning more strategies on how to Master your System Design Interview today with our Mastering the Systems Design Interview Course.
