Didn't apply (from a Hubspot office ex-USA) but had been approached on LinkedIn by a Hubspot recruiter, was who very nice, helpful and supportive. There were 4 rounds, the first of which was with the recruiter, covering motivations and other ex-professional achievements; round 3 with another manager; and round 4 was with a few directors. Throughout the interview process, there were questions related to knowing the product, the competitive landscape, your self awareness, motivations, and cultural fit. It seemed pretty clear that Hubspotters are infectious, people who are ready to engage and get a conversation going. Some questions that were a little different are rather common in the tech industries (teach me something) or related to Inbound Marketing, so read up and know your stuff before attempting any round.

I applied online and was contacted by a recruiter via e-mail. She sent along information about a video interview, although after some confusion I actually never ended up completing it and moving forward anyway. The recruiter and I had an informal phone conversation, after which she put me forward to a second round. I had to prepare three technical tasks before the second round, which consisted of two half-hour Google hangout sessions. One of the hangout sessions consisted of a screen-share where I explained how I completed the tasks. I heard back a few days later that I was invited to a third round of in-person interviews at the Cambridge office. When I came into the office, I spoke to three different support managers for a half-hour each and was given a tour of the office. My interview was on a Friday and they got back to me with an offer by the following Wednesday!