I was first screened by a recruiter. They gave a virtual group presentation to go over how Smoothstack worked and what you were signing up for. If you were still interested, they gave a brief technical interview and then a coding challenge. The coding challenge was 5 questions and included one debugging question (e.g. make this code work with as few changes as possible) and 2 shell scripting questions. The shell questions ended up being fairly easy but if you are not familiar with shell I'd definitely spend some time doing tutorials before starting the challenge. Overall it was more difficult than other interviews I had from similar companies for similar roles.

OA -> 15 minute recruiter screening -> 30 minute behavioral and technical interview demoing a personal project. Be familiar with OOP, databases, and a language of your choice. The process was fairly quick (1-2 weeks).