GET /search/

loc.gov:library-of-congress-api

Summary: Search everything on loc.gov
Operation ID: searchAll
Auth: none
Description

Search across all Library of Congress digital collections. Returns search results with pagination, facets, and result items.

Parameters (6)

at (string, query, optional)

Attributes to return (e.g., results, pagination, facets)

c (integer, query, optional, default: 25)

Count/items per page

fa (string, query, optional)

Facet filter for refining search results

fo (string, query, optional, default: json)

Output format

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

q (string, query, required)

Search term or query string

sp (integer, query, optional)

Start page number

Examples (6)

TitleTypeURLAction
Search across all Library of Congress collections openapi-spec https://www.loc.gov/search/?q=declaration of independence&fo=json
Search collections openapi-spec https://www.loc.gov/search/?q=cat&fo=json
Search across all Library of Congress content openapi-spec https://www.loc.gov/search/?q=baseball&fo=json&c=25&sp=1&fa=original-format:book&dates=1900/1950
Search across Library of Congress collections openapi-spec https://www.loc.gov/search/?fo=json&q=declaration of independence&c=25&sp=1&fa=original-format:book&all=True&sb=relevance&dates=1776-1800
Search across Library of Congress collections probe-gate https://www.loc.gov/search/?fo=json&q=declaration+of+independence&c=25&sp=1&fa=original-format%3Abook&all=True&sb=relevance&dates=1776-1800
Search everything on loc.gov probe-gate https://www.loc.gov/search/?fo=json&c=25

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-03-23 10:41:54.335885 200 2080ms
2026-03-23 10:36:02.742520 200 155ms
2026-03-23 10:28:27.316962 200 2681ms
2026-03-23 10:20:59.302624 200 3249ms
2026-03-23 10:11:57.371589 200 1156ms
2026-03-23 09:05:38.497509 200 1815ms

Response Changes

WhenOldNew
2026-03-23 10:11:57.371589 1399b38f6052 cbee79ee0b55
2026-03-23 10:20:59.302624 cbee79ee0b55 f15d6908f844
2026-03-23 10:28:27.316962 f15d6908f844 81b1152cd8dc
2026-03-23 10:36:02.742520 81b1152cd8dc cbee79ee0b55
2026-03-23 10:41:54.335885 cbee79ee0b55 912e0caa8777