It started with a phone screening. They basically just asked me some generic questions that could've been gleaned from my resume.
After the phone screen I was invited for an in-person interview. This was conducted by two very young people in senior positions. The questions were fairly easy and run of the mill. Overall, it was a decent interview. At the end, I didn't have very many questions for them and that seemed to figure poorly in their books for whatever reason.
My biggest takeaway was that this company still thinks of itself as a startup. Hokey posters all over the walls with Steve Jobs quotes, etc. Several mentions of Slack as their communication tool as if it's something new or revolutionary. They've been around for nearly a decade - at some point you stop being a startup, but they've stuck to that for their corporate culture. The work area was so quiet you could hear a pin drop. I took that as a big red flag that maybe people weren't happy, team oriented, or just completely introverted.
Overall though, they seem like nice people who care about doing decent work.