Did the Cigna senior SWE loop earlier this year. Passing on what I learned about the system design round specifically because that's where the real signal happens.
First: Cigna doesn't use L1-L7 FAANG-style leveling publicly. Internally it maps to something like Associate, Software Engineer, Senior SWE, Principal. The "senior" bar is roughly equivalent to L5 at Google or E5 at Meta in terms of scope expectations, though comp is lower.
The system design round was 60 minutes with two engineers. One was a hands-off note-taker, one drove the conversation. The prompt I got:
"Design a member-facing API that lets health insurance customers check their claim status, view EOB documents, and submit appeals."
Very domain-specific. This is on purpose: they want to see if you can think through healthcare data constraints (PHI, HIPAA, FHIR standards) without them having to spell it out. I didn't go deep on FHIR compliance but I did mention it as a constraint and they visibly lit up.
What they focused on: API design first (REST vs GraphQL, they pushed on this) Authentication: they cared a lot about how you handle session vs token-based auth for a healthcare portal. I talked through OAuth 2.0 flows. Data storage: document storage for EOBs (PDFs, large blobs), relational for claim records. They asked about the tradeoffs. Latency and throughput: this is a portal not a real-time system, so you don't need sub-100ms on everything. Stating that explicitly and designing accordingly seemed to impress them. Failure modes: what happens when the claims backend is slow, how do you gracefully degrade the appeal submission flow.
What they didn't ask about: Kafka or event streaming (nobody mentioned it) ML/AI integration (different team) Global scale or multi-region. They have a US-focus, don't design like it's Netflix.
Leveling signal from the debrief (recruiter shared some feedback): they look for whether a senior candidate drives the conversation, identifies constraints proactively, and makes reasonable tradeoffs explicit. At the principal level they reportedly expect you to challenge the problem framing itself.
If you're prepping, I'd spend time on: claims processing basics, HIPAA surface area in APIs, document storage patterns, and defensive API design. You don't need to be a healthcare domain expert but knowing the vocabulary helps.