CMS — Centers for Medicare & Medicaid Services

CMS Open Data API (data.cms.gov)

The CMS Open Data API exposes the full catalog of public CMS datasets — Medicare provider utilization and payment files, Medicare Advantage and Part D enrollment, Hospital Compare, Nursing Home Compare, Physician Compare, Open Payments (Sunshine Act), Marketplace public-use files, and the Provider Data Catalog. Datasets are queryable via filtered JSON/CSV downloads and dataset-level data-api endpoints.

CMS Open Data API (data.cms.gov) is one of 10 APIs that CMS — Centers for Medicare & Medicaid Services publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

This API exposes 1 machine-runnable capability that can be deployed as REST, MCP, or Agent Skill surfaces via Naftiko.

Tagged areas include Healthcare, Open Data, Datasets, Socrata, and Government. The published artifact set on APIs.io includes API documentation, an OpenAPI specification, and 1 Naftiko capability spec.

GitHub OpenAPI

Documentation

📖
Documentation
https://data.cms.gov/provider-data/

Specifications

⚙
OpenAPI
https://raw.githubusercontent.com/api-evangelist/cms-gov/refs/heads/main/openapi/cms-gov-open-data-openapi.yml

Other Resources

🔗
Portal
https://data.cms.gov/
🔗
Schema
https://data.cms.gov/data.json
🔗
NaftikoCapability
https://raw.githubusercontent.com/api-evangelist/cms-gov/refs/heads/main/capabilities/open-data-datasets.yaml

OpenAPI Specification

cms-gov-open-data-openapi.yml Raw ↑ 
openapi: 3.0.3
info:
  title: CMS Open Data API (data.cms.gov)
  description: |
    The CMS Open Data API exposes the public catalog of CMS datasets — Medicare provider
    utilization, Open Payments, Hospital/Nursing Home/Physician Compare, Marketplace
    public-use files, and more — via filtered JSON/CSV downloads and dataset-level
    data-api endpoints.
  version: '1.0'
  contact:
    name: CMS Open Data
    url: https://data.cms.gov/
  license:
    name: Public Domain (U.S. Government Work)
    url: https://www.usa.gov/government-works
servers:
- url: https://data.cms.gov/data-api/v1
  description: Production
- url: https://data.cms.gov/data.json
  description: DCAT catalog
paths:
  /dataset:
    get:
      summary: List Datasets
      operationId: listDatasets
      tags: [Catalog]
      parameters:
      - { name: keyword, in: query, schema: { type: string } }
      - { name: theme, in: query, schema: { type: string } }
      - { name: publisher, in: query, schema: { type: string } }
      responses:
        '200': { description: List of datasets, content: { application/json: { schema: { type: array, items: { $ref: '#/components/schemas/Dataset' } } } } }
  /dataset/{datasetId}:
    get:
      summary: Get Dataset Metadata
      operationId: getDataset
      tags: [Catalog]
      parameters:
      - { name: datasetId, in: path, required: true, schema: { type: string } }
      responses:
        '200': { description: Dataset metadata, content: { application/json: { schema: { $ref: '#/components/schemas/Dataset' } } } }
  /dataset/{datasetId}/data:
    get:
      summary: Get Dataset Data
      operationId: getDatasetData
      description: Filtered data query against a dataset distribution.
      tags: [Data]
      parameters:
      - { name: datasetId, in: path, required: true, schema: { type: string } }
      - { name: filter, in: query, schema: { type: string, description: 'Field filter expressions' } }
      - { name: keyword, in: query, schema: { type: string } }
      - { name: offset, in: query, schema: { type: integer } }
      - { name: size, in: query, schema: { type: integer, maximum: 5000 } }
      - { name: format, in: query, schema: { type: string, enum: [json, csv, tsv] } }
      responses:
        '200': { description: Dataset rows }
  /dataset/{datasetId}/data-stats:
    get:
      summary: Get Dataset Statistics
      operationId: getDatasetStats
      tags: [Data]
      parameters:
      - { name: datasetId, in: path, required: true, schema: { type: string } }
      responses:
        '200': { description: Row counts and column stats }
components:
  schemas:
    Dataset:
      type: object
      properties:
        identifier: { type: string }
        title: { type: string }
        description: { type: string }
        keyword: { type: array, items: { type: string } }
        issued: { type: string, format: date }
        modified: { type: string, format: date }
        publisher: { type: object }
        contactPoint: { type: object }
        accessLevel: { type: string }
        distribution: { type: array, items: { type: object } }
        theme: { type: array, items: { type: string } }