GET /search

loc.gov:library-of-congress-api

Summary: Search across all collections
Operation ID: searchAll
Auth: none
Description

Search for items across all Library of Congress digital collections

Parameters (6)

all (boolean, query, optional)

Include all items (true) or only digitized items (false)

dates (string, query, optional)

Date range filter (e.g., 1900/1950)

fa (string, query, optional)

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

fo (string, query, required)

Output format - must be 'json' for JSON response

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

q (string, query, optional)

Search query string

sp (integer, query, optional, default: 1)

Start page for pagination

Examples (3)

TitleTypeURLAction
Basic search for constitution curl https://www.loc.gov/api/search?q=constitution&fo=json
Search books from 1900-1950 curl https://www.loc.gov/api/search?q=civil%20war&dates=1900/1950&fa=original-format:book&fo=json
Paginated search for maps curl https://www.loc.gov/api/search?q=map&fa=original-format:map&sp=2&fo=json

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-03-23 10:23:04.765283 404 253ms
2026-03-23 10:09:54.464422 404 231ms
2026-03-23 09:42:13.171186 404 237ms

Response Changes

WhenOldNew
2026-03-23 10:09:54.464422 c3ffc078a7eb 20cbf6c326b0
2026-03-23 10:23:04.765283 20cbf6c326b0 5f00c7ae6552