Cancer.gov · Rate Limits
Cancer Gov Rate Limits
Cancer Gov Rate Limits is the machine-readable rate-limit profile for Cancer.gov on the APIs.io network, in the API Commons Rate Limits shape.
It captures 5 rate-limit definitions.
Limit state is signalled in the limit, remaining, reset, and retryAfter response headers.
The profile also includes response codes documented for throttled and note.
Tagged areas include Cancer, Federal Government, Healthcare, Research, and Clinical Trials.
5 Limits
limitremainingresetretryAfter
Transcribed from the provider's documentation on 2026-09-05 — api.seer.cancer.gov/terms (published limit), plus live un....
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CancerFederal GovernmentHealthcareResearchClinical TrialsGenomicsOpen DataDisease Surveillance
Limits
SEER*API published call ceiling per-key
5000/60 minutes
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'.
cancer-gov:clinical-trials-api
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.
cancer-gov:gdc-api
No rate limit documented at https://docs.gdc.cancer.gov/API/Users_Guide/Getting_Started/ and none signalled in headers.
cancer-gov:evs-api
No rate limit documented; the API is unauthenticated.
cancer-gov:glossary-api
No rate limit documented for any of the five unauthenticated webapis.cancer.gov services.
Work with this as data
Every rate limit here is available over the APIs.io API and to AI agents over MCP.