They emailed me first either from finding my work online or my Stack Overflow account. And after a round of resume and some standard questions over email they agreed to a phone screening. That was pretty chill but the person only somewhat knew about the tech so it was more about personal interaction. Then I got another phone interview with their CTO, which was much more about the tech, along with the usual questions about sorting algorithms and versioning conventions and stuff.
Then they agreed to an in-person interview. It essentially consisted of them sitting me down with an old crappy laptop that kept logging out every few seconds and they asked me to write an encrypted reverse proxy from scratch while simultaneously asking unrelated technical questions with a time limit. My only guess is that it was meant to test how people write code with distractions and stress? But their emphasis was more on that than on the technical skills so that might tell you something about the culture and work environment. It's probably a stress-fueled burnout race.