I skipped the phone interview since I had an employee's referral and went straight for the technical onsite interviews. There were five 1-hour long back-to-back technical rounds. The first round was a general design round with the hiring manager. He asked me some high level architecture questions, how to implement a REST API, etc. which were pretty basic. After that there were 3 coding interviews with a panel of 2 engineers in each round. My problem was that after giving you the initial question the interviewers gave me no time to think. Every time you pause to think your general solution or if you try coming up with a better approach they keep asking you more questions. Two of those interviews seemed to be interviewing the first time and almost seemed to have an agenda to put me down so he/she could look good to someone else. The questions weren't hard at all and in fact I ended up giving optimized solutions O(n) instead of standard brute-force solutions O(n^2). I felt like two of the six engineers themselves didn't quite understand why the solutions were better and ultimately although I nailed 2 of the 3 interviews I ended up not getting an offer. I guess I feel let down by the interview process cause although I took some more time, I ended up arriving at optimal solutions on 2 of the 3 coding challenges. I could have just gone for the simple, boring and brute-force solution but instead I tried to do better and they didn't seem to care or notice. The last round was on design and architecture by a senior engineer and I really enjoyed that interview. It was open ended and challenging enough and the interviewer seemed to know what he was doing as we dug deeper and deeper into the details.