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How to conduct effective system design interviews with a virtual whiteboard

Join CodeSignal CEO Tigran Sloyan and Co-Founder Sophia Baik in Data-Drive Recruiting Episode #40 as they discuss how to conduct an effective system design interview with a virtual whiteboard. In this episode you will learn about:

  • What is a system design interview and why it matters
  • How to effectively take the in-person whiteboarding session remote
  • Creating your candidate evaluation scorecard

The system design interview is largely considered part of the final stage of the in-person onsite interview for an engineering hire used to evaluate candidate’s ability to design scalable systems and architecture. Because a candidate is asked to draw the design on a whiteboard, it’s also widely known as a whiteboarding interview. Some companies, such as Google, conduct a whiteboarding session where they ask candidates to write codes on a whiteboard. But having candidates write codes on an IDE instead of a whiteboard creates a much better candidate experience and is much more realistic (engineers don’t write codes on a whiteboard once hired). Thus, for this blog post, we mean system design interviews when we say whiteboarding interviews.

Can we conduct effective whiteboarding interviews remotely?

Yes, say Sloyan and Baik, remote whiteboarding interviews can be as effective as in-person interviews when they are done correctly. Here are their best practices:

  • Use a collaborative virtual whiteboard to discuss the design. Check out CodeSignal Interview in which teams can conduct online technical interviews by toggling seamlessly between an IDE and a virtual whiteboard while on a video/audio call.
  • Save the coding portion for an IDE. Please do not try to write code on a whiteboard. Creating a great candidate experience during a remote interview is important. Use the right technology for the right situation to make the session effective and enjoyable. 
  • Develop a candidate evaluation scorecard to grade the candidate’s performance (more below). 

Tips for interviewers in conducting system design interviews

To keep things focused and fluid, begin your interview with the end goal in mind. Have you ever left a long-winded interview with a gut feeling on a candidate (i.e. I like this person), but no concrete evidence to back it up?

Start by asking yourself and your hiring committee what you’re seeking to assess. It’s critical to write down what exact skills or attributes you are expecting in your candidates for two reasons. First, it allows everyone on the hiring committee to be on the same page about the evaluation criteria. Second, system design interviews require a largely qualitative assessment approach.

While the exact evaluation criteria will be unique to your company to match the company’s product and development considerations, some thought-starters include:

  1. Memory considerations: with limited capacity, how much memory is being used and where is it being stored?
  2. Network considerations: users will have different network speeds; has the candidate thought about the impact of their design on user experience?
  3. Simplicity: if the candidate engineers something brilliant but no one understands it, then this solution cannot easily scale. 
  4. Keeping a cool head under pressure: how does the candidate handle having lots of information thrown at them? Are they flexible?

The interviewer can record a score for each attribute as they go through the interview;  if more digging is needed to assess performance, they can ask additional follow up questions to gain clarity. Implementing this structured and disciplined approach upfront empowers each interviewer to evaluate the specific attribute in a way that is consistent and fair. It also saves time later when making decisions between candidates.

Additional Resources