FWIW, I just accepted an offer from Instacart (my first day is Monday). Phase 1 of the interview process was a 10 minute coding problem on Hacker Rank. Phase 2 was building a small web app in half a day on my own time from my own apartment. Phase 3 was a 10 minute face to face coding problem that I solved using my normal programming environment on my own laptop. There were also conversational interviews with several people. No whiteboards were involved at any point.

They (er, we) are still hiring: https://www.instacart.com/jobs/engineering