Did a senior SWE system design round at Anthem last quarter, interviewing for what would loosely map to an L5 or senior IC role. Sharing notes because the healthcare context adds wrinkles you don't usually prep for.
The prompt was something in the family of: design a system that ingests and processes health claims data at scale, then surfaces relevant info to members and their care teams. I'm paraphrasing but that's the flavor.
What they were actually evaluating, as best I could tell:
Scale reasoning. They wanted to hear you acknowledge that healthcare data volumes are large but also irregular, spiky around plan enrollment periods and end of year. How does your ingestion pipeline handle a 10x burst in January?
Data sensitivity and compliance. HIPAA came up. You don't need to be a compliance lawyer but you should know that PHI (protected health information) changes your storage and access control requirements. Bring this up proactively, don't wait for them to ask.
API design. They asked how downstream consumers would query processed claims. REST vs GraphQL discussion happened. Neither answer was wrong but they wanted to see you reason about the consumer's needs.
Ops. They asked about observability. What do you monitor, how do you know when something is wrong, what does your alerting look like? SRE mindset, not just "throw it in CloudWatch."
I did not get grilled on specific AWS services or anything proprietary. Standard distributed systems vocabulary was fine: message queues, event streaming, read replicas, caching strategies.
Two things that tripped me up a little: I initially underweighted the audit trail requirement (in healthcare you need to know who accessed what and when) and I glossed over data retention policies. Both are genuinely important in this domain, so if you prep, add those to your checklist.
Total round was 45 minutes, one interviewer. Felt collaborative, not adversarial. They steered me when I was going sideways.