name: WorldCat API Rate Limits
description: >-
  OCLC WorldCat APIs enforce usage caps designed to meet typical member
  requirements while preserving network resources for all users. Rate limits
  vary by API and are applied on a rolling 24-hour window basis. Organizations
  with higher volume needs can request increased limits by contacting OCLC
  developer support with their WSKey and use case details.
url: https://www.oclc.org/developer/support/faq.en.html
created: "2026-06-13"
modified: "2026-06-13"

limits:
  - api: WorldCat Search API v2
    window: rolling 24-hour
    requests: 50000
    notes: >-
      Rolling 24-hour limit of 50,000 requests applies to the WorldCat Search
      API. This is consistent with the v1 limit before v1 was deprecated at
      end of 2024. Libraries needing higher limits should contact OCLC support.
    url: https://www.oclc.org/developer/api/oclc-apis/worldcat-search-api.en.html

  - api: WorldCat Knowledge Base API
    window: per day
    requests: 50000
    notes: >-
      Production access is limited to 50,000 requests per day. The API
      supports both OpenURL requests for matching citations and REST requests
      for browsing and searching subscription resources.
    url: https://www.oclc.org/developer/api/oclc-apis/worldcat-knowledge-base-api.en.html

  - api: WorldCat Metadata API
    window: per day
    requests: null
    notes: >-
      Specific rate limit figures are not published for the Metadata API.
      OCLC establishes usage caps in line with typical library cataloging
      workflows. Contact OCLC developer support for current limits.
    url: https://www.oclc.org/developer/api/oclc-apis/worldcat-metadata-api.en.html

  - api: WorldCat Entities Data API
    window: per day
    requests: null
    notes: >-
      Specific rate limit figures are not published for the Entities Data API.
      Access is limited to OCLC Meridian subscribers. Contact OCLC developer
      support for current limits applicable to your subscription.
    url: https://www.oclc.org/developer/api/oclc-apis/worldcat-entities-data.en.html

exceeding_limits:
  description: >-
    Organizations that need to exceed standard thresholds can request higher
    limits by emailing OCLC developer support with their WSKey and the specific
    API in question along with a description of the use case.
  contact: devnet@oclc.org
  url: https://www.oclc.org/developer/support/faq.en.html

authentication_note: >-
  All rate limits are enforced per WSKey (Web Services Key). OAuth 2.0 is the
  primary authentication method for current APIs. Legacy APIs may use API key
  (WSKey string) authentication. Rate limits apply per credential, not per
  IP address.