ClearPath Health operated a legacy claims adjudication system built in the early 2010s on a monolithic .NET architecture. The platform processed over 4 million claims per month for 12 million members across three states, but was buckling under scale. Critical pain points included 48-hour average claim processing times, frequent outages during peak enrollment periods, and an inability to integrate with newer provider networks using FHIR-based APIs. Their engineering team had attempted incremental modernization twice, but architectural debt made each attempt more expensive than the last. Regulatory pressure added urgency: upcoming CMS interoperability mandates required FHIR R4 compliance within 18 months, and the existing system had no path to get there.

We designed a phased migration strategy that allowed ClearPath to continue operating their existing system while we built the replacement in parallel. The new architecture used an event-driven microservices approach with clear domain boundaries. The claims processing engine was rebuilt using a rules-based pipeline with configurable adjudication logic, allowing business analysts to modify claim rules without engineering involvement. We implemented FHIR R4 endpoints for provider data exchange and member access, satisfying the upcoming CMS mandates. The data layer used PostgreSQL with read replicas for reporting, plus an event store for complete audit trails. We built a real-time dashboard that gave operations teams visibility into claim status, processing bottlenecks, and system health. Migration was executed using a strangler fig pattern, routing traffic gradually from the legacy system to the new platform over 8 weeks with automated rollback capabilities at each stage.