Did the full loop for a mid-level backend role on one of the data infrastructure teams. Six rounds total. Phone screen with HR, then a 45-min technical screen that was basically a warm-up DSA question in C++. Then the onsite: two more coding rounds, one system design, one behavioral, and a 'technical culture fit' chat with a senior engineer that was half interview half conversation.
The coding rounds were not LeetCode hard. More like medium-difficulty problems where they wanted you to talk through every decision. I explained why I was picking a hash map over a sorted array and the interviewer literally said 'good, that's what I wanted to hear.' The answer mattered less than the explanation.
System design was intense. Mine was around designing a real-time pricing feed for equities. If you don't know what bid-ask spread is or why latency matters in market data, go learn the basics before your design round. They're not expecting you to have financial domain expertise but 'I don't know what a tick is' will not help you.
Behavioral was straightforward. STAR format, ownership and collaboration questions. One around a time you disagreed with a technical decision and what happened.
Timeline was about 5 weeks start to finish. Offer came in on a Thursday, they gave me a week to decide.