The interview process began with a phone screen with the systems team lead, and a more junior engineer on that team. They told me that one of the purposes of this phone screen was to ensure that the systems team was the best fit for me, and re-stream me towards interviewing with another team if that was not the case. They also asked me about my expected salary range. They began by telling me about the role, and asked me some semi-technical questions about my past projects. They wanted examples of times I had applied an experimental/scientific approach to designing or troubleshooting equipment. After about a half hour long conversation, they told me that they would send me a technical take home test by email. The take home test was designed to take ~3 hours. It was a very specific question that was obviously related to a project that the systems team had been involved with. After the take home test I got an email saying that they wanted to bring me in to Boston for more interviews. When I interviewed at HQ I had three separate technical interviews. These interviews varied significantly in difficulty and duration. They also took me out to lunch with a few other engineers. The lunch was probably meant to include a conversation about the company. I actually used this time to ask them about life in Boston, living expenses, recreational activities and so forth, because I had never been in the city before. There were two things about my interview with the systems team at HQ that I really liked. I appreciated that they included a more junior engineer in the process, because in some ways he was more relatable to me. I also appreciated that they always found a way to make their questions concrete and easy to understand by using diagrams, physical models and other visual representations. I found it much easier to understand and solve their questions because they provided these reference materials. The day after my final three technical interviews I got a phone call from the recruiter telling me than they planned to extend me an offer and asking for my references. Overall my interview process went very smoothly and quickly. Apart from some typical delays around the holidays, communication was always very prompt. I emailed my recruiter many times throughout the process, and she always gave complete and reassuring answers to my questions.