First screening interview was on campus. This involved initial questions about my resume as well as two brain teasers. I wasn't able to actually completely solve either of them, but my thinking process was evidently sufficient for them to grant me an on-site in Chicago. Booked a room, flew out and then went through ~4 hours of interviews. First one was with the founder; it went terribly. He just couldn't get over the fact that I'm changing careers and wouldn't let it go. I completely aced all of the rest of the interviews, which were extremely easy (literally things I did in HS): programming a circular buffer, various number theory ques, various probability ques. Not suprisingly, acing the technical part didn't make up for the fact that the founder didn't like me! No offer.

I applied via their website. The HR reached out to me by mail for an interview with the business development team. I had a 2 hour zoom interview with them. I feel like that they brought me in only to gather information about the market and that they were not looking to hire.