: Search Collections

API: loc.gov:library-of-congress-apis
Endpoint: /search/
Response format: text/html +1 format
Auth: none
Method: GET
Last Status: 0

Description

Search the Library of Congress collections with optional JSON output format.

Parameters (5)

c (integer, query, optional)

Number of results per page

fa (string, query, optional)

Facet filter (e.g., original-format:book)

fo (string, query, optional)

Output format (json or yaml)

Constraints: {'enum': ['json', 'yaml']}

q (string, query, optional)

Search query string

sp (integer, query, optional)

Start page for pagination

Examples (3)

Search Library of Congress collections openapi-spec
curl 'https://www.loc.gov/search/?q=constitution&fo=json&fa=original-format%3Abook&c=25&sp=1&dates=1900%2F1950&all=True'
import requests

resp = requests.get(
    "https://www.loc.gov/search/",
    params={
        'q': 'constitution',
        'fo': 'json',
        'fa': 'original-format:book',
        'c': '25',
        'sp': '1',
        'dates': '1900/1950',
        'all': 'True',
    },
)
data = resp.json()
import zingu_apis

api = zingu_apis.api("library-of-congress-apis")
result = api.fetch("search/", q="constitution", fo="json", fa="original-format:book", c=25, sp=1, dates="1900/1950", all="True")

for item in result:
    print(item)
const resp = await fetch("https://www.loc.gov/search/?q=constitution&fo=json&fa=original-format%3Abook&c=25&sp=1&dates=1900%2F1950&all=True");
const data = await resp.json();
Search Library of Congress collections openapi-spec
curl 'https://www.loc.gov/search/?q=constitution&fa=original-format%3Aphoto'
import requests

resp = requests.get(
    "https://www.loc.gov/search/",
    params={
        'q': 'constitution',
        'fa': 'original-format:photo',
    },
)
data = resp.json()
import zingu_apis

api = zingu_apis.api("library-of-congress-apis")
result = api.fetch("search/", q="constitution", fa="original-format:photo")

for item in result:
    print(item)
const resp = await fetch("https://www.loc.gov/search/?q=constitution&fa=original-format%3Aphoto");
const data = await resp.json();
Search Collections openapi-spec
curl 'https://www.loc.gov/search/?q=history&fo=json'
import requests

resp = requests.get(
    "https://www.loc.gov/search/",
    params={
        'q': 'history',
        'fo': 'json',
    },
)
data = resp.json()
import zingu_apis

api = zingu_apis.api("library-of-congress-apis")
result = api.fetch("search/", q="history", fo="json")

for item in result:
    print(item)
const resp = await fetch("https://www.loc.gov/search/?q=history&fo=json");
const data = await resp.json();

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-04-16 17:25:32.882262 ERR
2026-04-16 02:29:51.359949 200 3646ms
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