openapi: 3.1.0
info:
  title: ClinicalTrials.gov Data API v2 Stats Studies API
  description: 'The ClinicalTrials.gov Data API v2 is a public REST API operated by the

    U.S. National Library of Medicine (NIH). It returns study records,

    metadata, statistics, search areas, and enumerations as JSON. Data is in

    the public domain and no authentication is required.

    '
  version: 2.0.0
servers:
- url: https://clinicaltrials.gov/api/v2
  description: ClinicalTrials.gov Data API v2 production
tags:
- name: Studies
paths:
  /studies:
    get:
      summary: Search studies
      description: 'Retrieve a paginated list of clinical study records. Supports

        free-text search, filtering, field selection, and pagination via

        nextPageToken.

        '
      parameters:
      - $ref: '#/components/parameters/Format'
      - $ref: '#/components/parameters/Query'
      - name: query.cond
        in: query
        schema:
          type: string
      - name: query.locn
        in: query
        schema:
          type: string
      - name: query.titles
        in: query
        schema:
          type: string
      - name: query.intr
        in: query
        schema:
          type: string
      - name: filter.overallStatus
        in: query
        schema:
          type: string
      - name: filter.geo
        in: query
        schema:
          type: string
      - $ref: '#/components/parameters/Fields'
      - $ref: '#/components/parameters/PageSize'
      - $ref: '#/components/parameters/PageToken'
      - name: countTotal
        in: query
        schema:
          type: boolean
      responses:
        '200':
          description: Studies page
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StudiesResponse'
            text/csv:
              schema:
                type: string
      tags:
      - Studies
  /studies/{nctId}:
    get:
      summary: Get a study by NCT ID
      parameters:
      - name: nctId
        in: path
        required: true
        schema:
          type: string
      - $ref: '#/components/parameters/Format'
      - $ref: '#/components/parameters/Fields'
      responses:
        '200':
          description: Study record
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Study'
        '404':
          description: Study not found
      tags:
      - Studies
  /studies/metadata:
    get:
      summary: Get study field metadata
      parameters:
      - name: includeIndexedOnly
        in: query
        schema:
          type: boolean
      - name: includeHistoricOnly
        in: query
        schema:
          type: boolean
      responses:
        '200':
          description: Study field metadata
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
      tags:
      - Studies
  /studies/search-areas:
    get:
      summary: Get search areas
      responses:
        '200':
          description: Search area definitions
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
      tags:
      - Studies
  /studies/enums:
    get:
      summary: Get controlled-vocabulary enumerations
      responses:
        '200':
          description: Enum values
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
      tags:
      - Studies
components:
  schemas:
    StudiesResponse:
      type: object
      properties:
        studies:
          type: array
          items:
            $ref: '#/components/schemas/Study'
        nextPageToken:
          type: string
        totalCount:
          type: integer
    Study:
      type: object
      properties:
        protocolSection:
          type: object
        derivedSection:
          type: object
        hasResults:
          type: boolean
  parameters:
    Format:
      name: format
      in: query
      description: Response format
      schema:
        type: string
        enum:
        - json
        - csv
        default: json
    PageSize:
      name: pageSize
      in: query
      schema:
        type: integer
        default: 10
        maximum: 1000
    Query:
      name: query.term
      in: query
      description: Free-text search term
      schema:
        type: string
    Fields:
      name: fields
      in: query
      description: Comma-separated list of study fields to return
      schema:
        type: string
    PageToken:
      name: pageToken
      in: query
      schema:
        type: string