The initial screen was followed by four coding, architecture, and behavioral interviews. All were pretty normal, about the same as most companies these days.

The design/architecture interview involved designing a system, a la "how would you implement Netflix." The programming interviews were challenging but not intractably difficult. They covered typical data structures and algorithms, with some efficiency and streaming topics relevant to Datadog's business mixed in.

Coding interviews were challenging but not impossible or brain teasers. Questions tested both general software engineering principles and were relevant to the position. Definitely some of the better interviews I've had.