posting the system design portion as its own thing since it deserves the detail. this was for a senior backend/platform role, so roughly L5-equivalent if you're mapping from big tech.
the prompt: they gave me a healthcare-specific scenario. something like: design a notification delivery system for clinical alerts, where a nurse or doctor gets a push notification, an in-app alert, AND a fallback SMS if they haven't acknowledged within 60 seconds. millions of hospital staff, high reliability requirement, needs audit logging for compliance.
the scenario isn't random. they seem to use variants of real problems from their systems. so it's worth thinking about healthcare-specific constraints before you go in: HIPAA compliance (what data can and can't go in a message payload) reliability > availability tradeoffs (hospitals can't miss critical alerts) audit logs are a hard requirement, not an afterthought legacy system integration is a real thing at a company this size
what they probed: the interviewer pushed pretty hard on failure modes. what happens if the push notification service is down? how do you guarantee delivery without double-sending? they also asked about how i'd handle the audit trail in a way that doesn't add latency to the critical path.
what mattered: thinking out loud, clearly. i drew the whole thing from scratch and narrated every decision. they seemed less interested in a perfect architecture and more in whether you could reason about tradeoffs. when i said "i'd use kafka for the event stream here," they immediately asked "why not a simple queue" and wanted me to articulate the tradeoff, not just say kafka.
what they didn't ask: nothing about ML, nothing about distributed consensus algorithms. no CAP theorem gotcha questions. more practical than academic.
duration: 55 minutes, then a few minutes for Q&A. felt like a reasonable amount of time.
if you're used to system design rounds at big tech companies, this is actually a bit more collaborative and less adversarial. the interviewer helped me when i got stuck on the SMS fallback piece rather than just watching me flounder.