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WorldCat Metadata API 2.0 release notes, July 2023


Release Date: July 13, 2023


This release of the WorldCat Metadata API 2.0 provides two enhancements in addition to two bug fixes.


  • Query your institution holding status by OCLC Number
  • Set or unset a holding using an OCLC Number contained in the 019 field of a bibliographic record

Bug fixes

  • Responses containing XML are missing the XML declaration on the first line of the response body
  • Calls submitting an existing full textual MARC or MARCXML record fail if any whitespace is in the 001 field

Many of these enhancements are the direct result of your feedback.

New features and enhancements

Query your institution holding status by OCLC Number (/manage/institution/holdings/current)

You can now query your institution holding status on one or more OCLC Numbers (up to 10). The response will contain JSON with the requested OCLC Number(s), the current OCLC Number(s), your institution's OCLC Symbol, and the holding status(es).  Holding status values are 'true' if set or 'false' if not set. The requested OCLC Number may differ from the current OCLC Number if records have been merged and the requested OCLC Number is now in an 019 field.

Example response for a request with 3 OCLC Numbers (11111 has a holding set, 12345 does not have a holding set, and 3832283820 does not exist)

    "holdings": [
            "requestedControlNumber": "3832283820",
            "currentControlNumber": null,
            "institutionSymbol": "OCWMS",
            "holdingSet": false
            "requestedControlNumber": "11111",
            "currentControlNumber": "11111",
            "institutionSymbol": "OCWMS",
            "holdingSet": true
            "requestedControlNumber": "12345",
            "currentControlNumber": "12345",
            "institutionSymbol": "OCWMS",
            "holdingSet": false

Set/unset a holding using an OCLC Number from the 019 field

Over time, some bibliographic records are merged together at OCLC and the non-retained record's OCLC Number is stored in the 019 field of the retained record. If the OCLC Number you are supplying has been merged into another bibliographic record, you can now use the OCLC Number of the non-retained record to set/unset a holding on the most current record. The response from the API call will have both the OCLC Number you requested as well as the 'current' OCLC Number of the record. If the current OCLC Number is different from what was submitted, consider updating your local data with the most current bibliographic record from WorldCat.

Example response, containing the current OCLC Number which differs from the requested OCLC Number contained in a MARC 019 field:

    "controlNumber": "767829842",
    "requestedControlNumber": "903702920",
    "institutionCode": "59357",
    "institutionSymbol": "OCWMS",
    "firstTimeUse": true,
    "success": true,
    "message": "Set Holding Succeeded.",
    "action": "Set Holdings"

Bug fixes

Responses containing XML are missing the XML declaration on the first line of the response body

API XML responses were missing the XML declaration "<?xml version='1.0' encoding='UTF-8'?>" at the beginning of the response.  Now, the XML declaration will be included on all API XML responses.

Calls submitting an existing full textual MARC or MARCXML record fail if any whitespace is in the MARC 001 field

If you submitted a textual MARC or MARCXML record for API calls that support submitting an entire record, the call would fail if any of the MARC 001 fields contained whitespace. Now, whitespace will be ignored and the call will successfully complete.

Important links

WorldCat Validation release notes

WorldCat Validation release notes provide current OCLC-MARC updates; changes to tagging conventions and coding practices for Bibliographic, Authority, and Holdings records; and new MARC codes. 

Virtual AskQC office hours

Join OCLC Metadata Quality staff to discuss WorldCat quality issues and cataloging questions. Visit AskQC for information about upcoming office hours, previous office hour recordings, and supporting materials.

Support website(s)

Support information for this product and related products can be found at: