ClinicalTrials.gov

aid: clinical-trials-gov
name: ClinicalTrials.gov
description: >-
  ClinicalTrials.gov is the U.S. National Institutes of Health (NIH)
  registry and results database of publicly and privately supported
  clinical studies of human participants conducted around the world.
  Operated by the National Library of Medicine (NLM), it provides a
  modern REST API (data-api v2) that returns study records, study
  metadata, search areas, and field definitions in JSON. The
  predecessor classic API remains available for legacy consumers but
  is being phased out in favor of the v2 API. Data is in the public
  domain and freely accessible without authentication.
type: Index
image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
url: https://raw.githubusercontent.com/api-evangelist/clinical-trials-gov/refs/heads/main/apis.yml
created: '2024-01-01'
modified: '2026-04-23'
specificationVersion: '0.19'
kind: government
tags:
  - Clinical Trials
  - Government
  - Health
  - NIH
  - Open Data
  - Public Health
  - Research
apis:
  - aid: clinical-trials-gov:data-api-v2
    name: ClinicalTrials.gov Data API v2
    tags:
      - Clinical Trials
      - REST
      - Search
      - Studies
    image: https://kinlane-productions2.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    baseURL: https://clinicaltrials.gov/api/v2
    humanURL: https://clinicaltrials.gov/data-api/api
    properties:
      - url: https://clinicaltrials.gov/data-api/api
        type: Documentation
      - url: https://clinicaltrials.gov/data-api/about-api
        type: About
      - url: openapi/clinical-trials-gov-data-api-v2-openapi.yml
        type: OpenAPI
    description: >-
      The ClinicalTrials.gov Data API v2 is the modern public REST
      interface to the NIH clinical-studies registry. It exposes
      study records, study metadata, search areas, study fields,
      version history, and statistics endpoints. Responses are JSON
      by default and the API is open and unauthenticated. The base
      URL is https://clinicaltrials.gov/api/v2 and operations include
      /studies, /studies/{nctId}, /studies/metadata,
      /studies/search-areas, /studies/enums, /version, and /stats.
  - aid: clinical-trials-gov:classic-api
    name: ClinicalTrials.gov Classic API
    tags:
      - Clinical Trials
      - Legacy
      - REST
    image: https://kinlane-productions2.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    baseURL: https://clinicaltrials.gov/api
    humanURL: https://clinicaltrials.gov/data-api/api
    properties:
      - url: https://clinicaltrials.gov/data-api/api
        type: Documentation
    description: >-
      The Classic API is the legacy ClinicalTrials.gov interface that
      preceded the Data API v2 and exposes full-study, brief-study,
      and field-values endpoints with XML, JSON, and CSV responses.
      It is being deprecated in favor of the v2 REST API and remains
      online for backward compatibility while consumers migrate.
  - aid: clinical-trials-gov:bulk-downloads
    name: ClinicalTrials.gov Bulk Downloads
    tags:
      - Bulk
      - Datasets
      - Open Data
    image: https://kinlane-productions2.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://clinicaltrials.gov/data-api/about-api/csv-download
    properties:
      - url: https://clinicaltrials.gov/data-api/about-api/csv-download
        type: Documentation
    description: >-
      ClinicalTrials.gov provides bulk CSV and JSON downloads of the
      full study registry through the data-api download endpoints.
      These artifacts support large-scale analytics, archival, and
      offline mirrors of the registry without making per-record
      API calls.
  - aid: clinical-trials-gov:aact
    name: AACT Database
    tags:
      - Analytics
      - Database
      - Postgres
      - Research
    image: https://kinlane-productions2.s3.amazonaws.com/apis-json/apis-json-logo.jpg
    humanURL: https://aact.ctti-clinicaltrials.org/
    properties:
      - url: https://aact.ctti-clinicaltrials.org/
        type: Documentation
      - url: https://aact.ctti-clinicaltrials.org/data_dictionary
        type: Data Dictionary
    description: >-
      AACT (Aggregate Analysis of ClinicalTrials.gov) is a publicly
      available relational database of all ClinicalTrials.gov study
      content maintained by the Clinical Trials Transformation
      Initiative (CTTI) at Duke University. It is updated daily and
      is widely used by researchers as a SQL-friendly mirror of the
      registry.
common:
  - type: Website
    url: https://clinicaltrials.gov/
  - type: About
    url: https://clinicaltrials.gov/about-site
  - type: Documentation
    url: https://clinicaltrials.gov/data-api/api
  - type: Portal
    url: https://clinicaltrials.gov/data-api
  - type: Glossary
    url: https://clinicaltrials.gov/study-basics/glossary
  - type: News
    url: https://clinicaltrials.gov/about-site/announcements
  - type: Help
    url: https://clinicaltrials.gov/help
  - type: PrivacyPolicy
    url: https://www.nlm.nih.gov/privacy.html
  - type: TermsOfService
    url: https://clinicaltrials.gov/about-site/terms-conditions
  - type: GitHub
    url: https://github.com/clinicaltrialsgov
  - type: JSONLD
    url: json-ld/clinical-trials-gov-context.jsonld
  - type: Spectral
    url: rules/clinical-trials-gov-rules.yml
  - type: Naftiko Capabilities
    url: capabilities/clinical-trials-gov.yaml
maintainers:
  - FN: Kin Lane
    email: [email protected]