specification: API Commons Plans
specificationVersion: '0.1'
schema: https://raw.githubusercontent.com/api-evangelist/interface-research/main/schema/api-commons.yml#/$defs/Plans
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, https://www.cancer.gov/syndication/api, https://docs.gdc.cancer.gov/API/Users_Guide/Getting_Started/
  and https://gdc.cancer.gov/support. Replaces a 2026-05-04 bulk-sweep scaffold whose tier limits and
  prices were placeholder defaults, not provider-published values.
plan_count: 1
note: 'Cancer.gov is a US federal government (National Cancer Institute) API estate. There are no priced
  tiers, no paid plans and no billing on any of its APIs — access is free, and where a key is required
  it is issued free on self-service registration. The one forward-looking caveat NCI itself publishes
  is in the SEER API terms of service: SEER ''reserves the right to charge fees for future use'' for high-volume
  or certain commercial applications. Nothing is charged today.'
currency: USD
plans:
- id: cancer-gov-free
  name: Free / open government access
  type: free
  price: 0
  currency: USD
  billing_period: null
  overage: null
  description: The only tier NCI offers across every API in this record. Registration requirements differ
    per service rather than per tier.
  access:
  - api: cancer-gov:clinical-trials-api
    key_required: true
    how: Free API key from the CTS Developer Accounts portal at https://clinicaltrialsapi.cancer.gov/,
      sent as X-API-KEY.
    quota: null
    quota_note: NCI publishes no request quota for this API.
  - api: cancer-gov:seer-api
    key_required: true
    how: Free account; key sent as X-SEERAPI-Key.
    quota: 5000 calls per 60 minutes
    quota_note: The only numeric quota NCI publishes anywhere on this estate — see https://api.seer.cancer.gov/terms.
  - api: cancer-gov:gdc-api
    key_required: false
    how: Open-access data and the GraphQL endpoint answer anonymously. Controlled-access data and submission
      require an X-Auth-Token downloaded from the GDC Data Portal.
    quota: null
    quota_note: No quota published.
  - api: cancer-gov:evs-api
    key_required: false
    how: 'No authentication. Verified live: GET https://api-evsrest.nci.nih.gov/api/v1/metadata/terminologies
      returns HTTP 200 anonymously.'
    quota: null
    quota_note: No quota published.
  - api: cancer-gov:glossary-api
    key_required: false
    how: No authentication on any of the five webapis.cancer.gov services (glossary, drugdictionary, sitewidesearch,
      bestbets, r4r).
    quota: null
    quota_note: No quota published.
  entries: []
future_pricing:
  stated: true
  api: cancer-gov:seer-api
  quote: SEER 'reserves the right to charge fees for future use' for high-volume or certain commercial
    applications.
  source: https://api.seer.cancer.gov/terms