Did the loop for a senior backend role. Four rounds total: recruiter call, a 45-min coding screen with a fairly standard graph problem, then a two-part virtual onsite. System design and behavioral on the same day.
The system design was genuinely hard. Not in a tricky-question way, just in the real-constraints way. They asked me to design a timeline feed. Classic Twitter problem, obviously. But they pushed hard on the read/write tradeoffs at scale and wanted concrete numbers, not hand-waving. I've done this problem at other interviews and it was fine. Here they kept asking "what happens when this breaks at 200k RPS" and I had to actually know.
Behavioral was one round with a senior eng. Not HR-vibes at all. It was basically "walk me through a time you owned something end to end" and then two hours of follow-ups. Very focused on what I personally did vs. what the team did. They can tell when you're using 'we' to hide solo contributions.
Feedback timeline was fast. Heard back in 4 business days. Got an offer, turned it down for comp reasons. The base was competitive but the RSU package was in X Corp equity and I just couldn't get comfortable with that.
If you're prepping: scale, ownership, and be honest about what you built vs. what your team built.