Karat Interview Details

To help you prepare for your Karat interview, we want to share details of what your interview will look like and what you will be assessed on. This post lists details of how your interview will be structured and assessed, as well as tips that candidates find helpful for succeeding in their interview. If you have any questions about any of this, please don’t hesitate to contact us or your recruiter before your interview.

Interview philosophy

In general, we want your interview experience to be as much like regular on-the-job programming as possible. Doing so yields a better experience for you, and gives us a more accurate sense of your skills. With that said, we understand that your interview will never be perfectly analogous to regular on-the-job programming, as much as we strive for it to be. For example, there are tighter timing constraints than most work projects have, and the situation is higher-pressure than your average work day.

We’ve structured our interviews with both of these ideas in mind: Making it more like a regular programming experience, but also being cognizant of the ways in which it fundamentally differs from a regular programming experience. As a result, our interviews may have some notable differences from other interviews you’ve done.

Interview format

For most interview formats, most of your interview will consist of programming. Depending on the role you’re interviewing for (check with your recruiter if you’re not sure), you’ll spend:

• 10 to 20 minutes on something like a project discussion, knowledge questions relevant to the role, or a skills test like a code review.
• 30 or 45 minutes programming. We’ll ensure you get the allotted time on programming, regardless of how long the previous sections took.
• There are always multiple programming problems available; if you finish a given problem and there is time remaining, we will ask you a new problem.

  Note: some interview formats, for example some manager-level roles, don’t include any direct programing. Again, check with your recruiter if you have questions.

For each programming problem, you will:

• Be presented with the problem
• Have an opportunity to ask clarifying questions
• Be asked to describe an algorithm
• Choose your language (unless a language is specified for the problem) and code up your algorithm in the coding environment
• Fix any bugs or edge cases
• Once your solution is fully working, you’ll be asked to describe your solution’s time and space complexity. (Note that if your solution differs from the original algorithm you described, that’s OK. We’ll ask you to explain the time and space complexity of whatever your final solution was.)

How the interview is assessed

For the initial, non-programming section, how it is assessed will vary depending on the topic. The Interview Engineer should explain this to you at the beginning of the section, but don’t hesitate to ask your interviewer if you have any questions about how you’re being evaluated.

For the programming section:

• You will primarily be judged on the extent to which you solve each problem. Focus on getting to fully-working solutions.
• The optimality of your solution is factored in, but is secondary. When deciding how optimal a solution is, we’ll focus on its Big-O time and space complexity.
• Other factors like code quality and how much testing you do are recorded but not meaningfully factored into your assessment.
• We’ve chosen these priorities not because we think that things like code quality are unimportant, but because we find that assessing you on a small number of factors and being explicit about what they are creates a better interview experience.
• For example, have you ever had an interview where part of your mental cycles were being spent trying to discern what the Interview Engineer did/didn’t care about? Or where you were being judged on six different factors and weren’t sure which one to prioritize? We strive to help you avoid this as much as possible, so you can focus on thinking about the problems in front of you.
• Your Interview Engineer will help coach you through this if you have questions or they notice you spending extra time on something that won’t meaningfully factor into your assessment.

Programming section details

• The programming problems will not require esoteric data structures; our problems are designed to be solvable with data structures you use regularly and that are available in the standard library for the majority of languages. Examples: Lists, arrays, strings, stacks, queues, hash tables, sets.
• There is no penalty for compiling/running your code. Run it and test it as much as you want! Candidates generally do better if they run their code more, quickly testing each piece of functionality as they build it rather than having to debug all of their code at once at the end.
• You are allowed to look up API references while programming (as you would be on the job), but knowing the most common operations for the most common data structures will save you time, as it does on the job.
• You may speak as much or as little as you want while programming. Your Interview Engineer will offer small tips or ask questions if you’re completely stuck, but they will be watching you code and will be able to follow along whether you’re verbalizing as you code or not.

Tips for performing better

• Practice programming problems if you haven’t recently. You don’t need to spend weeks on this, but most candidates report that spending at least an hour or two brushing up on basic algorithms and data structures and doing a few practice problems on sites like Codewars is helpful.
• Strategize your approach around the two things we are judging you most on: Your ability to create working solutions to the problem, and to a lesser extent the optimality of your solution. If you have a working algorithm in mind but aren’t sure if it’s optimal, don’t spend more than a minute or two trying to find a more optimal approach. Your Interview Engineer will help guide you on this decision.
• The problems are designed so that you shouldn’t need to rush, but don’t spend time gold-plating a solution when you could be moving on to the next problem. As with all things time management, your Interview Engineer will help guide you on this; if they feel you are spending extra time on something that won’t meaningfully factor into your evaluation, they will let you know.
• Test your code as you build it, as mentioned above. The extent to which you test won’t be factored into your assessment (not because testing isn’t important, but to minimize the number of things you need to think about prioritizing during your interview), but quickly testing each piece of functionality as you build it can help keep the overall complexity down as you build up your solution.
• Similarly, factoring your code cleanly and using sensible variable names may be helpful to keep things clear in your head. As noted above, though, you won’t be judged on this – just because you write an overly-long function in a time-constrained interview doesn’t mean you’re incapable of factoring your code well on the job.
• If you’re unsure about anything, ask your Interview Engineer. Our problems are designed to not have “gotchas” and to be as unambiguous as possible, but it’s natural that there may still be areas of the question that you’re unclear on or that you’d like clarified. Make a point to ask about these as soon as they occur to you; your interviewer will welcome it!
• When you’ve solved a problem, take 30-60 seconds quickly thinking through whether you have any edge case bugs before saying your solution is complete. There is a slight penalty if an Interview Engineer needs to point out an edge case to you vs. you discovering it yourself. Don’t spend more than a minute on this, though; the penalty is small and it will be better to move on than to spend too much time double-checking your solution. Again, your interviewer will help you navigate this situation: they’ll ask you to double check that you think the problem is fully working and encourage you to move on if it’s in your best interest.

Hopefully this has been helpful and makes you feel better-prepared for your interview. If there’s anything we can do or any questions we can answer to further help in your preparation, please let us know!