League·Software Engineer·Onsite - System Design / Architecture
Jul 2026
System design round at League for a Software Engineer position. The whole thing was one big design question about an insurance claims processing system, end to end. Pretty involved, lots of moving parts.
- Design an end-to-end insurance claims processing system for a health insurer, covering the full claim lifecycle from submission through validation, human review, and payment.
- Walk through the state machine for claim processing and explain how you'd make each state transition atomic while preventing two adjusters from processing the same claim simultaneously.
- How do you avoid the dual-write problem when a claim approval needs to both update the database and trigger a payment?
- A pending-info SLA timer fires on a claim waiting for member documents. What does your system do, and why might auto-denying by the clock be the wrong call for a health insurer?
- A payment request to the external processor times out with no response. How does your system guarantee the provider gets paid exactly once when you retry?
- An admin tightens a coverage rule. Should that change retroactively affect claims already adjudicated under the old rule, and how do you version rules to prevent silent re-adjudication?
- Adjuster search across claims gets slow as data grows. How do you serve queries like 'all under-review claims for member X over $500, sorted by age' without hammering the transactional database?
“Big open-ended one.”