Referred to Simon Data via a recruiter. First round was conversational chat, then the technical round. The interviewer was extremely nice and helpful, but the question was so esoteric and unrelated to the day to day, that it was unfair to ask when candidates are expected to know so much else. There should've been some notice or study guide in the previous round to let candidates know that the typical React, CSS, algorithms, or data structures required every else don't apply.