The loc.gov JSON/YAML API provides structured, machine-readable data about Library of Congress digital collections — books, photographs, maps, manuscripts, archived websites, videos, and more. No authentication is required. Responses are available in JSON or YAML format via the fo= query parameter.
openapi: 3.0.3
info:
title: loc.gov JSON/YAML API
description: >
The loc.gov JSON/YAML API provides structured, machine-readable data about
Library of Congress digital collections — books, photographs, maps,
manuscripts, archived websites, videos, and more. No authentication is
required. Responses are available in JSON or YAML format via the fo= query
parameter.
version: '1.0'
contact:
name: Library of Congress
url: https://www.loc.gov/about/contact-us/
license:
name: U.S. Government Work
url: http://www.loc.gov/text-us-government-work
externalDocs:
description: API Documentation
url: https://www.loc.gov/apis/json-and-yaml/
servers:
- url: https://www.loc.gov
description: Production server
tags:
- name: search
description: Search across all loc.gov digital collections
- name: collections
description: Browse and access digital collections
- name: formats
description: Browse items by format type
- name: items
description: Access individual item details
paths:
/search/:
get:
tags:
- search
summary: Search all loc.gov resources
description: >
The /search endpoint searches everything on the www.loc.gov website.
This includes items in the collection, legislation, web pages, blog
posts, events, and press releases. The q parameter is required.
operationId: searchAll
parameters:
- name: q
in: query
description: Search query term
required: true
schema:
type: string
example: baseball
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: at
in: query
description: >
Limit response to specific attribute(s). Use dot notation for nested
attributes (e.g., results.0).
required: false
schema:
type: string
example: results
- name: fa
in: query
description: >
Facet filter. Used to narrow results by a specific facet value.
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number for pagination
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: Successful search results
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/collections/:
get:
tags:
- collections
summary: List all digital collections
description: >
Returns a list of all the digital collections at the Library of
Congress. Collections are listed under the results attribute.
operationId: listCollections
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: at
in: query
description: Limit response to specific attribute(s)
required: false
schema:
type: string
example: results
- name: sp
in: query
description: Starting page number for pagination
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of digital collections
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/collections/{collectionSlug}/:
get:
tags:
- collections
summary: Get a specific digital collection
description: >
Returns the web presentation of a specified digital collection in JSON
format. The collection name must be in kebab-case (e.g.,
abraham-lincoln-papers or baseball-cards).
operationId: getCollection
parameters:
- name: collectionSlug
in: path
description: >
URL slug for the collection (kebab-case, e.g., civil-war-maps,
baseball-cards, abraham-lincoln-papers)
required: true
schema:
type: string
example: civil-war-maps
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: at
in: query
description: Limit response to specific attribute(s)
required: false
schema:
type: string
- name: q
in: query
description: Search term to filter collection items
required: false
schema:
type: string
- name: fa
in: query
description: Facet filter
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number for pagination
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: Collection data
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/audio/:
get:
tags:
- formats
summary: Browse audio recordings
description: Returns items in the Audio Recordings format from loc.gov digital collections.
operationId: listAudio
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: at
in: query
description: Limit response to specific attribute(s)
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of audio recording items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/books/:
get:
tags:
- formats
summary: Browse books and printed materials
description: Returns items in the Books/Printed Material format from loc.gov digital collections.
operationId: listBooks
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: at
in: query
description: Limit response to specific attribute(s)
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of book and printed material items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/film-and-videos/:
get:
tags:
- formats
summary: Browse films and videos
description: Returns items in the Films/Videos format from loc.gov digital collections.
operationId: listFilmAndVideos
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: at
in: query
description: Limit response to specific attribute(s)
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of film and video items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/manuscripts/:
get:
tags:
- formats
summary: Browse manuscripts and mixed materials
description: Returns items in the Manuscripts/Mixed Material format from loc.gov digital collections.
operationId: listManuscripts
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of manuscript items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/maps/:
get:
tags:
- formats
summary: Browse maps
description: Returns items in the Maps format from loc.gov digital collections.
operationId: listMaps
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of map items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/newspapers/:
get:
tags:
- formats
summary: Browse newspapers
description: Returns items in the Newspapers format from loc.gov digital collections.
operationId: listNewspapers
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of newspaper items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/photos/:
get:
tags:
- formats
summary: Browse photos, prints, and drawings
description: Returns items in the Photos/Prints/Drawings format from loc.gov digital collections.
operationId: listPhotos
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of photo, print, and drawing items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/notated-music/:
get:
tags:
- formats
summary: Browse printed music and sheet music
description: Returns items in the Notated Music (sheet music) format from loc.gov digital collections.
operationId: listNotatedMusic
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of notated music items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/web-archives/:
get:
tags:
- formats
summary: Browse web archives
description: Returns items in the Web Archives format from loc.gov digital collections.
operationId: listWebArchives
parameters:
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: q
in: query
description: Search query to filter results
required: false
schema:
type: string
- name: sp
in: query
description: Starting page number
required: false
schema:
type: integer
minimum: 1
- name: c
in: query
description: Number of results per page
required: false
schema:
type: integer
minimum: 1
maximum: 150
responses:
'200':
description: List of web archive items
content:
application/json:
schema:
$ref: '#/components/schemas/SearchResponse'
/item/{itemId}/:
get:
tags:
- items
summary: Get item details
description: >
Returns bibliographic information and digital resources for a single
item identified by its identifier. The item ID can be obtained from the
id field in search results. Many items are composed of one or more
resources; the item endpoint provides summary information about each
resource and how to access it.
operationId: getItem
parameters:
- name: itemId
in: path
description: The item identifier (from the id field in search results, excluding the base URL)
required: true
schema:
type: string
example: 2003623100
- name: fo
in: query
description: Output format
required: false
schema:
type: string
enum:
- json
- yaml
example: json
- name: at
in: query
description: Limit response to specific attribute(s)
required: false
schema:
type: string
responses:
'200':
description: Item bibliographic data and digital resources
content:
application/json:
schema:
$ref: '#/components/schemas/ItemResponse'
'404':
description: Item not found
components:
schemas:
SearchResponse:
type: object
description: Standard search result response from the loc.gov JSON API
properties:
facets:
type: object
description: Available facets for filtering results
additionalProperties:
type: array
items:
$ref: '#/components/schemas/FacetValue'
pagination:
$ref: '#/components/schemas/Pagination'
results:
type: array
description: List of collection items matching the query
items:
$ref: '#/components/schemas/ItemSummary'
FacetValue:
type: object
description: A facet value used to filter search results
properties:
count:
type: integer
description: Number of results matching this facet
link:
type: string
description: URL to filter results by this facet value
value:
type: string
description: The facet value text
Pagination:
type: object
description: Pagination information for search results
properties:
count:
type: integer
description: Total number of items in the result set
current:
type: integer
description: Current page number
from:
type: integer
description: Index of the first item on the current page
last:
type: integer
description: Index of the last item on the current page
next:
type: string
nullable: true
description: URL for the next page of results
of:
type: integer
description: Total number of pages
perpage:
type: integer
description: Number of items per page
previous:
type: string
nullable: true
description: URL for the previous page of results
results:
type: string
description: Human-readable description of current result range
to:
type: integer
description: Index of the last item on the current page
ItemSummary:
type: object
description: Summary information for a single collection item in search results
properties:
date:
type: string
description: Date associated with the item
description:
type: array
items:
type: string
description: Descriptions of the item
id:
type: string
description: URL identifier for the item (use to query the item endpoint)
image_url:
type: array
items:
type: string
description: URLs for item thumbnail images
index:
type: integer
description: Index position in results
item:
type: object
description: Bibliographic metadata for the item
additionalProperties: true
language:
type: array
items:
type: string
description: Languages of the item
location:
type: array
items:
type: string
description: Geographic locations associated with the item
original_format:
type: array
items:
type: string
description: Original format types of the item
partof:
type: array
items:
type: string
description: Collections or groups this item belongs to
subject:
type: array
items:
type: string
description: Subject headings for the item
title:
type: string
description: Title of the item
type:
type: array
items:
type: string
description: Type classifications of the item
url:
type: string
description: URL for the item's HTML page on loc.gov
ItemResponse:
type: object
description: Detailed item response from the loc.gov item endpoint
properties:
cite_this:
type: object
description: >
Experimental feature providing citation text in Chicago Manual of
Style, MLA, and APA formats. Should be used as a starting point
only.
additionalProperties: true
item:
type: object
description: Bibliographic information for the requested item
additionalProperties: true
resources:
type: array
description: >
Digital resources associated with the item (digitized images,
audio files, video files, web archive links, etc.)
items:
$ref: '#/components/schemas/Resource'
Resource:
type: object
description: A discrete digital representation or element of a collection item
properties:
caption:
type: string
description: Caption for the resource
files:
type: array
description: Digital files associated with the resource
items:
type: array
items:
$ref: '#/components/schemas/ResourceFile'
image:
type: string
description: URL of the resource image
url:
type: string
description: URL of the resource
ResourceFile:
type: object
description: A specific digital file for a resource
properties:
height:
type: integer
description: Height of the image in pixels
levels:
type: integer
description: Number of zoom levels available
mimetype:
type: string
description: MIME type of the file
size:
type: integer
description: File size in bytes
url:
type: string
description: URL to access the file
width:
type: integer
description: Width of the image in pixels