Community Health Systems Formulary API

openapi: 3.1.0
info:
  title: Community Health Systems Patient Access Claims Formulary API
  description: Community Health Systems provides healthcare interoperability APIs pursuant to the CMS Interoperability and Patient Access Final Rule (CMS-9115-F). The Patient Access API allows third-party applications to retrieve data concerning adjudicated claims, encounters, formulary data, and clinical data using FHIR standards.
  version: '2026-01-01'
  contact:
    name: Community Health Systems
    url: https://www.chs.net
servers:
- url: https://api.chs.net/fhir/r4
  description: FHIR R4 Production Server
security:
- oauth2: []
tags:
- name: Formulary
  description: Formulary and medication data
paths:
  /MedicationKnowledge:
    get:
      operationId: searchFormulary
      summary: Search formulary
      description: Retrieve formulary and medication information.
      tags:
      - Formulary
      responses:
        '200':
          description: FHIR Bundle of MedicationKnowledge resources
          content:
            application/fhir+json:
              schema:
                $ref: '#/components/schemas/Bundle'
components:
  schemas:
    Bundle:
      type: object
      properties:
        resourceType:
          type: string
          const: Bundle
        type:
          type: string
        total:
          type: integer
        entry:
          type: array
          items:
            type: object
            properties:
              resource:
                type: object
  securitySchemes:
    oauth2:
      type: oauth2
      flows:
        authorizationCode:
          authorizationUrl: https://api.chs.net/oauth2/authorize
          tokenUrl: https://api.chs.net/oauth2/token
          scopes:
            patient/*.read: Read access to patient data
            launch/patient: Patient launch context
externalDocs:
  description: CMS Interoperability Final Rule
  url: https://www.cms.gov/regulations-and-guidance/guidance/interoperability/index