A recruiter reached out to me and immediately set up a phone interview with an Engineering Manager. He mostly asked questions about my experience and things I've worked on, diving into some technical details of past projects. The phone interview went well, so a few hours later, I received an invitation for an on-site interview.

The on-site interview consisted of a tour of the offices with the recruiter, followed by three one-hour technical interviews, each with one member of the engineering team. The last one was via Google Hangout with an engineer based in the Cambridge, US office.

The technical interviews started with about 10-15 minutes of chatting about past and current projects, my experience, etc., and then moved onto technical questions that involved whiteboarding.

The technical questions were challenging but not out of the ordinary. The first round was on algorithms, while the second and third rounds were on database and system design, but nothing too complex. Interviewing with HubSpot can be one of the most enjoyable interview experiences you'll ever have. I would encourage you to be super collaborative and inquisitive.

Your soft skills will be very important, as their team culture is core to their values, and figuring out solutions together in small teams is crucial. So, ask your interviewer questions and use them like team members, trying to work with them on the solution. No one expects you to know everything; it's more about your process of figuring things out and using your resources.

For me, that was probably the best part of the interview process: working with them on the solution, asking questions for a second opinion, and thinking out loud (e.g., "Okay, if I go for this approach and use this, I will end up with a nested loop, dependent quadratic complexity O(n^2). Maybe I should go for a nested linear logarithmic loop and change the inner loop to a divide by 2, ending up with a complexity O(n log2 n).").

In summary, all rounds were interactive and fun. I just loved it and would do it again. Working with those guys in a team must be great. Even though I didn't get an offer, I was really disappointed because I thought that for my 2+ years of commercial experience as a software engineer, I did quite well.

Their feedback was: "very positive from a cultural/personality side, but just not strong enough on the tech side." This is why, below, I will provide you with the full set of questions and my answers. So, please prepare thoroughly before going into an interview with HubSpot and don't waste this opportunity; I just loved every minute I spent there. In other words, you have to do better than I did, so keep reading below under the Interview Questions and good luck.

The first question was on algorithms.

The second question was on system design. I was asked to design the database for a Facebook-like app.

The third question was again on system design, but this time on the URL shortener, REST API, and DB design.