Went through 5 x 45min sessions with 5 different people. Mostly solving riddles on a whiteboard, but also some diagram drawing and general architecture discussion (including databases and distributed network, which — as front-end engineer — I obviously have nothing to do with). Overall, interview felt very generic and impersonal (unlike interviewing at Facebook, for example, where they actually knew what I specialize in and were excited to bring me in to work on specific projects). As a front-end engineer specializing in Javascript, I was interviewed by people that don't necessarily work with Javascript or do any front-end work. The riddles were about abstract problems and were generally (in my opinion) medium-hard difficulty.