Pretty standard startup process, faster than big companies but higher bar. Requires a solid foundation and in depth knowledge of one of the techs that are bing used. Technical round is a leetcode-like but not really question, looks like they care about the thought process and communication skills In addition to a good answer.

The interview process was split in 4 parts. There was an online coding assessment. An initial 1 hour interview, then a more in depth 3 hour technical interview. Finally there's a multiple hour take home coding challenge.