Indigo's recruiter reached out to me and indicated I should apply online (you just upload a resume and optional cover letter). After that I received an invitation to do a video-recorded interview, which was relatively easy, if incredibly awkward. I think they use this to weed out the very poor candidates.
The in-person interview is super intense and took 3-4 hours. Be prepared to take a half a day off work. I was first interviewed by someone from HR, then by 3 supervisors in the department. Each interview is one-on-one and takes 30-60 mins. The one negative things is that scheduling the interview was disorganized. I was contacted by a few different people and scheduled for varying lengths of time and locations as we worked out a good appointment time. I think this is just a result of them being a startup and having to work out the kinks while they establish procedures.
The questions were all things you would expect in an interview, with the exception of what they call a "who" interview, which one person gets tasked with. They take you all the way down your resume and ask you why you did certain things, how you felt about the choices you made, whether you enjoyed or disliked jobs, schools, etc.
I'm still not sure how I feel about the "who" interview. The purpose is to get to know you how you think and how you make decisions, which I can see the benefit of. However, I don't find the choices I made and things that I felt when I was 17, college-aged or even 5 years ago are accurately reflective of the person I've become in the time that has passed since then (my resume starts with a time that was well over a decade ago).
Overall, it was a good experience. The people are friendly and don't feel intimidating regardless of the intensity of the questions they are asking you. They even feed you lunch.
