The interview process was lengthy. After connecting via AngelList we exchanged several emails, I went through a skype interview, an interview project, two further phone interviews, and then an onsite. The interview project was fairly involved, requiring about 10 hours. During the onsite interview I met the entire team, including the half in another city via teleconference.
When I initially spoke with them over email, I told them I did not have the skills they were looking for, but they talked me in to interviewing anyway. Ultimately I did not get an offer for the same reason. While the interview process was engaging, if my lack of those skills was a deal-breaker it seems like they could have saved both of us a lot of time by ending it sooner.