Very friendly interviewer who made the conversation feel collaborative rather than stressful. He asked a lot of thoughtful questions about core concepts and how you would actually design and build different systems. The interview was fairly math heavy, emphasizing logical reasoning, problem decomposition, and precise thinking rather than rote coding. Overall, it felt rigorous but fair, and you could tell he genuinely wanted to understand your thought process.

The initial screening was an online coding assessment via CodeSignal. It was proctored, you're given 70 minutes to complete 4 questions. It's the same format as their standard proctored general assessment. The first two questions are on pretty basic topics (like arrays). The second two are leetcode medium. The third question has to be brute forced, but you're told what to do. For the last question, you need to figure out the solution yourself, it should be clever and efficient. If you don't instantly know the solution to the problems, or have to debug, you will not complete the exam. The actual problems were not difficult, but I felt like I needed more time. Matroid requires you to successfully complete all 4 questions to move on to the next stage.

Going over the resume, a common "what happens when you visited 'google.com'" problem, then building simple a React frontend todo list app, and finally some follow ups about how to improve its scalability and performance.