PatentRef

Data version 20261027.2, as of 2026-10-27: the build these pages were checked against. API version 1.21.0.

/api/v1/patent/us_application_citation/

Upstream view USApplicationCitationList (index us_application_citations, response key us_application_citations). Any field may be null where the bulk data has no value. Default fields (f): patent_id, citation_document_number, citation_sequence. Default sort (s): [{"patent_id": "asc"}]. Default options (o): {"pad_patent_id": false}. When the build in service does not carry this endpoint's data set it answers 501 with X-Status-Reason-Code ERR_NOT_IMPLEMENTED and X-Status-Reason naming the data set.

Routes
GET POST /api/v1/patent/us_application_citation/ GET POST /api/v1/patent/us_application_citation/{pk}/
Response key
us_application_citations
Default f
patent_id, citation_document_number, citation_sequence
Default s
[{"patent_id": "asc"}]
Default o
{"pad_patent_id": false}
q
required on the list route
Detail key
patent_id in the path; a "/" in a key is written ":"

Example

curl -s -G -H "X-Api-Key: $KEY" https://patentref.io/api/v1/patent/us_application_citation/ \
  --data-urlencode 'q={"patent_id": "10000000"}'
import json, os, requests

base_url = "https://patentref.io"
headers = {"X-Api-Key": os.environ["PATENTREF_KEY"]}
params = {"q": {"patent_id": "10000000"}}
r = requests.get(base_url + "/api/v1/patent/us_application_citation/", headers=headers,
                 params={k: json.dumps(v) for k, v in params.items()})
r.raise_for_status()
data = r.json()
print(data["total_hits"], data["us_application_citations"][:3])

Fields

Kind is how q treats the field (grammar, Field kinds). Sortable fields go in s. Nested fields are named with a dot in q and f; naming the group returns its upstream fields, and a field whose note says it is present only when f names it comes back only then. The rows of a group come in the order of their source (grammar, the response and paging).

FieldTypeKindSortableNote
patent_idstringkeywordyes
patentstring (URL)keywordLink to the detail record: https://patentref.io/api/v1/patent/<id>/, with a "/" in the id written ":"; null when the id is null. Kind: keyword: in q this name matches the id behind the link (for example "H01" for cpc_current.cpc_class), not the URL.
citation_sequenceintegernumberyes
citation_document_numberstringkeywordyes
citation_wipo_kindstringkeywordyes
citation_categorystringkeywordyes
citation_datestringdateyes
citation_namestringkeywordyes

Machine-readable: this page's data as JSON, and the operation in openapi.json (operationId USApplicationCitationList).