[Must Read] System Design Interview Preparation Guide
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System DesignInterview

System Design Interview Preparation Guide

I spent a couple of months preparing for system design interviews, and let me tell you—it’s a journey. Over time, I went through a ton of resources but eventually narrowed it down to a few game-changers that made all the difference. Thanks to these, I ended up landing offers from multiple big tech companies.

The LeetCode community has been super helpful throughout my prep, so I wanted to give back with this post. If you’re gearing up for system design interviews, here’s a list of awesome resources and tips that’ll help you crush it.

1. The Basics

1a. System Design Primer by Donne Martin
  • Link: System Design Primer
  • Start here. Don’t even bother looking anywhere else. Just open this link and go through every single topic mentioned.
  • The fundamentals are what set you apart in interviews. Knowing the "what" and "why" behind concepts will make you a stronger candidate.
  • This guide is super detailed, and the step-by-step explanations are gold. It’s all about building a rock-solid foundation.
  • Pro tip: Interviewers love to dive into details about your solutions. So, trust me—get those foundational concepts crystal clear before tackling problems.
1b. Designing Data-Intensive Applications (DDIA)
  • This book by Martin Kleppmann is next level. It’s perfect for understanding data systems, distributed systems, and database design.
  • If you can read it cover to cover, you’re basically on your way to becoming a system design expert. Seriously, every page is a gem.
  • If you’re short on time, skim it. But if you can, make it a habit to read it a little every day—it’s totally worth it.

2. Amazing Videos

  • System Design Interview - YouTube Channel
    • Run by Mikhail, this channel is just chef’s kiss. He’s also the instructor for LeetCode’s premium system design course.
    • There aren’t many videos, but each one is packed with knowledge bombs. Watch them carefully and absorb every single solution he explains.
    • Heads up: A 30-minute video might take hours to fully digest because you’ll want to pause, research, and explore related topics. Totally worth it, though.

3. Alex Xu: The OG

  • Once you’ve got your basics down, grab both versions of Alex Xu’s system design books.
  • The second book is especially detailed and a must-read.
  • Here’s the hack: If the book mentions, say, distributed transactions using 2PC, go the extra mile and dive deep into 2PC. Expand your understanding beyond the pages.

4. Hello Interview Channel: Structuring Your Approach

  • Hello Interview - YouTube Channel
    • This channel is all about how to structure your approach during system design interviews.
    • Once your basics are solid, these videos will help you level up your presentation, communication, and visual representation skills.
    • If you want to sound like a senior engineer during interviews, watch these.

5. Practice, Practice, and Practice

  • Mock interviews are your best friend. Practice with friends, coworkers, or even your parents (yes, really). The more you practice presenting your ideas, the better.
  • Platforms like Exponent offer free mock interviews—take advantage of them.
  • For diagrams, I swear by Excalidraw. It’s hands down the best tool for this.

6. The Interview

  • Most of the interviews will be of 1-hour duration.

  • Time breakdown:

    • Introduction: 5-10mins ( try to be super duper fast with the introduction so that you can save those precious minutes for later, trust me an interview ends before you could realize whats going on!!)
    • Problem statement: 5mins ( Ask clarifying questions and make sure you have an agreement with the interview on what are you going to design. Failing to have this agreement will lead to mis-communications and multiple iterations later on)
    • Time window for you to ask questions to the interviewer at the end: 5min.

  • If you see you will only have 35min-40min to do the actual desing. So make sure you manager your time well. Whatever be your style of interviews, make sure you have an AGREEMENT with the interviewer.

  • Lets say you feel you dont need back of the envelope estimation right now and defer it for later, communicate to the interviewer that you will take it up later when needed and doing that calculation might not be useful.

  • Treat your interviews as your team mate and make sure you take his/her thoughts and go ahead before moving forward.

  • You have 30mins to show your NINJA-level system design skills that you have learnt over the past few months of hardwork, so make sure you speak up and keep communicating a lot. So keep the COMMUNICATION going.

  • Drive the interview, be on the PILOT seat. Interviews like it when you drive the interview and they just help you with minor inputs. Incase you feel you are expert in an area, drive the interview towards that direction

  • Be prepared to get grilled or interviewers who make you uneasy or put you in a tough spot. Does not matter how much you getting grilled, keep smiling and moving forward. Dont get nervous and give it all. I have done the mistake and paid the price. So, be calm, composed and continue the momentum.

  • So summarizing these are the important things in the interview:

    • Be Confident
    • Make an agreement with the interviewer.
    • Clarify
    • Communicate, Communicate and Communicate
    • Close and conclude the design with a brief walk through.
    • Complete the interview, and get the offer you have been working hard for.

In case you wanna stay connected, please drop your linkedIn profile, I will send you a connection request.

Follow these resources and tips, and you’ll be ready to crush your system design interviews. You’ve got this!

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