generated: '2026-09-06'
method: searched
source: >-
  https://clinicaltrials.gov/about-site/release-notes,
  https://clinicaltrials.gov/data-api/about-api/api-migration,
  https://clinicaltrials.gov/api/v2/version (live probe 2026-09-06)
versioning:
  scheme: semver-in-path
  current_version: 2.0.5
  version_in: path
  version_pattern: https://clinicaltrials.gov/api/v2
  discovery_endpoint: https://clinicaltrials.gov/api/v2/version
  evidence: 'GET https://clinicaltrials.gov/api/v2/version -> 200 {"apiVersion":"2.0.5","dataTimestamp":"2026-09-04T09:00:06"}'
  note: >-
    Only the MAJOR version appears in the URL path. Minor releases (2.0.1, 2.0.2 … 2.0.5)
    ship in place and are announced on the release-notes page; there is no way to pin a
    minor version and no version header is returned on data responses.
data_freshness:
  cadence: daily
  evidence: >-
    "ClinicalTrials.gov is updated daily" — https://clinicaltrials.gov/about-site/terms-conditions;
    the live /version endpoint exposes dataTimestamp (2026-09-04T09:00:06 when probed).
  note: >-
    dataTimestamp is the single most useful freshness signal for an agent and is machine-readable.
deprecation:
  policy_published: true
  policy_url: https://clinicaltrials.gov/data-api/about-api/api-migration
  headers:
    sunset: false
    deprecation: false
    note: >-
      No RFC 8594 Sunset or Deprecation header was observed on any live response
      (headers on GET /api/v2/studies checked 2026-09-06).
  retirements:
  - api: ClinicalTrials.gov Classic API
    status: retired
    announced: '2024-03-19'
    retired: '2024-06'
    replacement: https://clinicaltrials.gov/api/v2
    evidence: >-
      Release notes announce the classic website and API retirement; probed 2026-09-06,
      https://clinicaltrials.gov/api/query/full_studies?expr=cancer&fmt=json returns HTTP 404
      and https://clinicaltrials.gov/api/info/data_vrs returns HTTP 404.
    note: >-
      NLM gave roughly a full quarter of public notice plus a written migration guide, and
      then hard-404'd the surface. Consumers still calling /api/query/* get no Sunset header
      and no JSON error — only an nginx HTML 404.
  deprecated_operations: []
  deprecated_operations_note: >-
    No operation in any openapi/ document carries `deprecated: true`.
support:
  status_page: null
  status_page_note: >-
    No status page is published for ClinicalTrials.gov or for NLM (status.nlm.nih.gov does
    not resolve, checked 2026-09-06). Outages are announced in-page and via the NLM
    Technical Bulletin.
  sla: null
  sla_note: >-
    No SLA, uptime target or support-response commitment is published. The API is a free
    U.S. Government public-data service.
  support_url: https://support.nlm.nih.gov/
  support_evidence: 'probed 2026-09-06 -> HTTP 200'
release_notes:
  url: https://clinicaltrials.gov/about-site/release-notes
  cadence: irregular, roughly quarterly
  note: See changelog/clinical-trials-gov-changelog.yml for the structured recent entries.