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FLEX FHIR Platform

Welcome to the FLEX FHIR (R4) Developer Documentation. This site provides: - API discovery and interactive testing using Swagger UI - Authentication & authorization guidance (OAuth 2.0 / SMART-on-FHIR) - Sandbox usage patterns and ready-to-run requests - Best practices for secure and performant FHIR integrations

Environment Base URL
https://int2.flexoptumcare-nonprod.optum.com/fhir/R4/

What is FLEX FHIR?

FLEX FHIR exposes HL7® FHIR® R4 resources over a secure REST API. It adheres to industry standards: - HTTPS (TLS 1.2+) for transport security - OAuth 2.0 & OpenID Connect (OIDC) for authentication - SMART-on-FHIR scopes for healthcare-specific authorization

  • Getting Started → Your first call in 5 minutes
  • Authorization → OAuth 2.0 + SMART scopes (see top nav)
  • Sandbox → Example patients, sequences, and test data (see top nav)
  • FAQ → Answers to common questions (see top nav)

Interactive API (Swagger UI)

Use the embedded Swagger UI to explore endpoints, schemas, and try live calls with your access token.

Note: Swagger UI requires an OpenAPI document. For FHIR servers, generate one from your CapabilityStatement and publish it as /docs/openapi.json. See instructions in Getting Started → Generate OpenAPI.