I applied online. The process took 4 weeks. I interviewed at CallFire (Los Angeles, CA) in May 2017
Interview
It was a long process; taking place over the course of a month. I lived in the Los Angeles area, so your mileage may vary. In hindsight, the process was so long because CallFire is tedious in finding both a candidate that is qualified and a candidate that fits into the company's culture.
I had an initial phone screen which was more of HR pitching the company to me. They were more excited to talk to me than I was to talk to them. I then came in for a short 30-45 minute in-person interview by a group. It was largely comprised of tech questions with culture and career question preceding.
The following week I had a 1-on-1 phone interview with someone unable to be in the area at the time. This was a more open interview about tech in general.
My last set of interviews were with various people in senior management. I received the most interesting interview exercises I have ever been posed in these interviews; I cannot sum them up any better than that.
Overall, the interviews themselves became progressively open-ended. They want you to talk, they want to see that you are thinking, and they are not scared to call your BS. CalllFire has two main things they look for in new employees: culture fit and potential. They want to get to know you, and they want to know that you can grow as opposed to stagnating after knowing everything upon arrival.
Know the fundamentals, be open, be creative, be ready to talk, and your interviews will go well.