openapi: 3.1.0
info:
  title: Community Health Systems Patient Access Claims 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: Claims
  description: Adjudicated claims and encounter data
paths:
  /ExplanationOfBenefit:
    get:
      operationId: searchClaims
      summary: Search claims
      description: Retrieve adjudicated claims data as ExplanationOfBenefit resources.
      tags:
      - Claims
      parameters:
      - name: patient
        in: query
        required: true
        schema:
          type: string
      responses:
        '200':
          description: FHIR Bundle of ExplanationOfBenefit 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