Got contacted by MongoDB, since they had my resume from last year. I went through a 45 minute technical interview by phone, then another 45 minute phone interview, and finally three interviews onsite. I felt the onsite interview questions were not that difficult, but I tunnel visioned too hard on one approach and missed an easy solution.

Basic data structure runtime questions and Dsa quirks and then some code for 2 problems. It was a one-hour interview, where I had fully explain my thought process at each stage. They wanted to understand my what you were thinking and then they would let you code. Majority of the time was spent on coding and a little bit on runtime analysis. They care about correctness over anything else mostly, so for the first stage don't worry about optimality. Just focus on being correct and ask clarifying questions.