New York City is home to both the country's largest health systems and a rapidly growing digital health ecosystem. From major academic medical centers building patient engagement platforms to health-tech startups developing clinical decision support tools, FHIR R4 is the common language that connects them. Zerosums Technologies provides FHIR development services for both sides of that equation. For NYC health systems, we implement the FHIR infrastructure required by CMS interoperability rules — Patient Access APIs, Provider Directory APIs, and Payer-to-Payer Data Exchange. We build FHIR servers, configure EHR FHIR endpoints, map HL7 v2 and CDA data to FHIR resources, and expose well-documented APIs that your partners and patients can consume. For NYC digital health companies, we provide the FHIR engineering needed to connect to Epic, Cerner, and other EHR platforms through their FHIR APIs. We implement SMART on FHIR authorization flows, FHIR resource subscriptions, and bulk data export for population health analytics. We help startups launch faster by building reliable FHIR integration layers so product teams can focus on their clinical applications. NYC's health-tech community also benefits from our experience with New York's regulatory environment. We understand NYDFS data requirements for health plans, NYS DOH data governance expectations, and the compliance frameworks that NYC digital health companies encounter as they scale.