4 rounds. First was a generic programming challenge. Then a systems design. Then another system design oriented at you. Then a final programming challenge with the CEO. Overall it was a pretty straightforward process. They were quick to book times. However, some of the interviewers are based in the UK so interviews were rather early.

Received an email from their recruiter, standard questions about prior experience and about programming languages I had worked in. Next interview was a coding round with the CTO. Just one question and general discussion around the solution.