Managing Your Time
Learn how you can effectively manage your time in the interview.
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Managing your time
All of the advice in this handbook revolves around the goal of getting you to a reasonable stage of success in 45 minutes. Most System Design Interviews are 45 minutes long, but this doesn’t mean you have 45 minutes to design your system.
It’s important to consider budgeting your time and structuring your conversation to hit all the right notes in your limited time frame.
Budgeting time
Within your 45 minutes, you’ll want to budget time for the following:
Introductions and icebreakers—5 minutes
Being asked questions at the end—5 minutes
This leaves you 30-35 minutes to solve the problem. Even in those 35 minutes, you’re not designing the whole time. You’re asking clarifying questions and checking on assumptions, which leaves about 20-25 minutes of actual designing.
To ensure you get a solid 20-25 minutes of designing, here are some tips to help you manage your time well.
Limit your clarifying questions
When designing a real-world system, you’d probably make a two-week exploratory journey with stakeholders. But in your interview, you just need enough detail to start moving forward with a solution.
Asking questions will help you make a well-informed decision on trade-offs. However, you don’t have all the time in the world to do this. Besides, you can’t possibly hash out all the requirements for a real-world system in 45 minutes.
To make the most of this time, ask questions to:
Collect information to help you put the big black boxes on the whiteboard.
Identify the core functional requirements of your system.
Try to limit your clarifying questions to 10 minutes—5 minutes at the beginning of the interview and 5 minutes throughout the interview (if needed).
Expect (and accept) some ambiguity
Keep in mind that sometimes you’ll have to decide on your trade-off. You can’t get hung up on a lack of specific details, so you’ll have to move on as best you can with what you have, even if it feels ambiguous.
Being able to move forward with some ambiguity is a good signal to your interviewers. Needing too many prompts and too much support may leave the impression that you won’t be able to work independently.
Avoid the rabbit hole
Ideally, you’ll want the opportunity to demonstrate all the knowledge you have to your interviewers. But you should also be mindful of doing this, in the interest of time.
I often see people make the mistake of trying to show exceptional knowledge too early in their interview. They end up going down a rabbit hole. But this isn’t what interviewers want. Rather, they want an overview of how the system works first—you can zoom in and go into detail later.
If you go down a rabbit hole too early, the interviewer may not get the signal that you understand the big picture, which will make you seem less hireable. The key to making sure you hit all the right points within your 45-minute interview is to start wide, then go deep—in an area that’s appropriate to your level—later in your interview.
From breadth to depth
When shaping the conversation, you’ll want to start broad and become more pointed toward the end.
In the beginning, you’ll be given a vague problem that you seek to understand better. You’ll start by talking superficially about many solutions and components. Be mindful not to go too in-depth into the complexities of one aspect at this point.
Towards the end, after you’ve done a high-level design, you can start talking about a handful of things in detail. This shows your ability to zoom in and zoom out based on the requirements and where your team is at. You can think of this as an upside-down pyramid—start wide, and go deep toward the end.
Remember: There’s nothing wrong with allowing you and the interviewer to move on to another topic by saying, “I’m sorry. I don’t understand [x] at this level. My understanding is quite superficial and I honestly don’t know more about it at this time.”
Staying in your lane
If you’re a junior engineer, reaching beyond your grasp to try and address more senior-level concerns won’t necessarily impress your interviewers. Rather, it may leave a strange impression.
When you go in-depth, consider your lane—and stay in it. Your lane is defined by the level of the role you’re applying for and the needs of the role itself.
It can also be exciting to demonstrate your knowledge in a particular specialization. Still, you should balance your enthusiasm with a grounded understanding of what the interviewer wants to hear from you. Sometimes you won’t have the time to get specific in the area of your choice, and this is okay. Prioritize the expectations for your role over cramming in irrelevant topics.
Keeping the time
To help manage your time during the interview, remember these key takeaways:
Budget only 20-25 minutes for your design process.
Budget 5-10 minutes for your clarifying questions.
Cover the high-level design of your solution before discussing more in-depth, specific topics.
