specification: API Commons Rate Limits
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/RateLimits
provider: Cancer.gov
providerId: cancer-gov
created: '2026-05-04'
modified: '2026-09-05'
generated: '2026-09-05'
method: searched
source: https://api.seer.cancer.gov/terms (published limit), plus live unauthenticated response-header
  inspection on 2026-09-05 of https://webapis.cancer.gov/glossary/v1/..., https://api.seer.cancer.gov/rest/glossary/latest,
  https://api.gdc.cancer.gov/status and https://api-evsrest.nci.nih.gov/api/v1/metadata/terminologies.
  Replaces a 2026-05-04 bulk-sweep scaffold whose headers and per-tier numbers were placeholder defaults.
limit_count: 1
note: Exactly one NCI API publishes a numeric rate limit, and no NCI API signals rate-limit state at runtime.
  The scaffold this file replaces asserted a full X-RateLimit-* header family that the estate does not
  actually return.
headers:
  limit: null
  remaining: null
  reset: null
  retryAfter: null
  policy: null
  observed: false
  note: No X-RateLimit-*, RateLimit-* or Retry-After header appeared on any live response probed. The
    security headers these services do return (Strict-Transport-Security, X-Content-Type-Options, X-Frame-Options,
    Content-Security-Policy) carry no throttling signal. An agent therefore cannot see itself approaching
    SEER's documented ceiling and can only discover it by being cut off.
responseCodes:
  throttled: null
  note: No status code for exhaustion is documented by any service, and none was observed.
limits:
- api: cancer-gov:seer-api
  name: SEER*API published call ceiling
  scope: per-key
  window: 60 minutes
  limit: 5000
  burst: null
  published: true
  source: https://api.seer.cancer.gov/terms
  quote: 5000 API calls per 60 minute time period.
  note: The terms add that the limit 'may change from time to time at SEER's sole discretion, effective
    immediately upon posting', and that 'programmatic methods intended to subvert rate limiting are considered
    a violation of the terms'.
- api: cancer-gov:clinical-trials-api
  published: false
  limit: null
  note: NCI publishes no rate limit for the Clinical Trials Search API on any of its own surfaces (clinicaltrialsapi.cancer.gov
    is a single-page app that serves an HTML shell for every path, and https://www.cancer.gov/syndication/api
    states none). Third-party integration guides circulate a '50 requests per minute' figure; it is not
    sourced to NCI and is deliberately not recorded here.
- api: cancer-gov:gdc-api
  published: false
  limit: null
  note: No rate limit documented at https://docs.gdc.cancer.gov/API/Users_Guide/Getting_Started/ and none
    signalled in headers.
- api: cancer-gov:evs-api
  published: false
  limit: null
  note: No rate limit documented; the API is unauthenticated.
- api: cancer-gov:glossary-api
  published: false
  limit: null
  note: No rate limit documented for any of the five unauthenticated webapis.cancer.gov services.