a few colleagues have asked me about Humana's system design interview since i went through it earlier this year for a Staff / Senior-equivalent SWE role. writing this up properly.
first: Humana doesn't use the L1-L7 ladder terminology publicly, but internally there's a leveling structure. "Senior" there maps to what i'd call IC4-ish. the role i interviewed for was "Senior Software Engineer II" which is a step above standard senior.
the system design round itself
45 minutes. one interviewer, sometimes a second shadowing. the prompt i got: design a real-time member eligibility verification API that downstream providers and pharmacies call to check coverage. the system needs to handle burst load during enrollment periods, tolerate upstream payer data latency, and stay HIPAA-compliant.
that's a lot. they're not expecting you to fully solve it. they want to see how you scope, how you prioritize, and whether you surface the right constraints unprompted.
things that seemed to land well: asking about SLA targets before drawing anything calling out read-heavy vs write-heavy access patterns explicitly mentioning caching strategy with cache invalidation considerations specific to eligibility data (stale data here has real member impact) touching on circuit breakers and graceful degradation when upstream payer systems are slow HIPAA: field-level encryption, audit log completeness, minimum necessary access
things i fumbled a bit: i jumped to microservices without asking team size and ownership context. the interviewer gently probed on that. for Humana, monolith-first thinking may actually be the right answer depending on team context.
prep recommendations
distributed systems fundamentals still matter. but layer in healthcare-specific context: payer/provider data flows, FHIR APIs, PHI handling. even surface-level awareness of these will separate you from candidates who prep on pure tech company case studies.
overall the interviewer was fair and gave cues. not adversarial.