Senior Healthcare Interoperability Engineer -- 100% Remote -- C2C/W2 Profile

Job Title: Senior Healthcare Interoperability Engineer Location: Remote Key Responsibilities • Design and build FHIR R4–compliant APIs using .NET 8+ • Implement CMS-mandated APIs: • Patient Access API • Provider Access API • Payer-to-Payer Data Exchange • Prior Authorization API • Provider Directory API • Integrate and configure Smile CDR for CMS compliance • Implement Da Vinci FHIR IGs (PAS, PDex, CDex, HRex, CRD, DTR) • Develop HL7 v2/v3 and X12 (278, 837, 835) processing and transformations • Build Prior Authorization workflows, including CRD and DTR • Architect and develop a custom FHIR server (resource persistence, search, validation) • Ensure HIPAA compliance, auditing, and security • Integrate with EHRs, claims systems, PBMs, and external FHIR endpoints • Optimize performance for high-volume healthcare data Required Skills (Must Have) • 7+ years of C#/.NET development (preferably .NET 8+) • Deep expertise in FHIR R4 (resources, profiles, extensions, IGs) • Strong knowledge of HL7 v2.x / v3 • CMS Interoperability & Prior Authorization Final Rule experience • Da Vinci FHIR IGs: PAS, PDex, CDex, HRex, CRD, DTR • Experience building FHIR APIs from scratch • SQL Server (complex queries, performance tuning) • Clinical terminologies: LOINC, SNOMED CT, RxNorm, ICD-10, CPT, HCPCS • Azure experience (App Service, API Management, Service Bus, Key Vault) Nice to Have • Hands-on Smile CDR configuration and customization • Experience with HAPI FHIR, Firely Server, Azure API for FHIR • SMART on FHIR, OAuth 2.0, OIDC, UDAP • FHIR Bulk Data ($export), Subscriptions • X12 EDI processing (278, 837, 835, 270/271) • Firely .NET SDK, NHapi • React + TypeScript (provider/member portals)