Library of Congress

The Library of Congress is the largest library in the world, with millions of books, films and video, audio recordings, photographs, newspapers, maps and manuscripts in its collections. The Library is the main research arm of the U.S. Congress and the home of the U.S. Copyright Office. The Library publishes a suite of public APIs that expose its catalog, digital collections, historic newspapers, and legislative information.

Library of Congress publishes 12 APIs on the APIs.io network, including Bills API, Collections API, Committees API, and 9 more. Tagged areas include Cultural Heritage, Federal-Government, Library, Legislative, and Newspapers.

Library of Congress’ developer surface includes authentication, documentation, engineering blog, and 7 more developer resources.

🌐 Visit website 📡 Source on GitHub

31.3/100 thin ▬ flat Agent 35/100 agent ready Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0

AccessFreemiumSelf serve⚡ Free to try

12 APIs

Cultural HeritageFederal-GovernmentLibraryLegislativeNewspapersSearch

Kin Score

Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0

Composite quality — 31.3/100 · thin

Contract Quality 10.5 / 21

Developer Ergonomics 5.3 / 17

Access Clarity 2.7 / 17

Operational Transparency 1.2 / 11

Contract Governance 0.0 / 10

Discoverability 6.3 / 9

Regulatory Posture 5.0 / 15

Agent readiness — 35/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 4 / 4

Regulatory Posture applies to this provider. Its tags matched the Education & Research regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/library-of-congress: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 12

Individual APIs this provider publishes, each with its own machine-readable definition.

Open Collections 16

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Rate Limits 1

Documented rate limits and quota policies.

Library Of Congress Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

AGENTIC

Resources

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

Reference

Reference

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 3

Authentication, authorization, and security posture

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Authentication

Authentication

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Source (apis.yml)

aid: library-of-congress
name: Library of Congress
description: The Library of Congress is the largest library in the world, with millions of books, films and video, audio recordings,
  photographs, newspapers, maps and manuscripts in its collections. The Library is the main research arm of the U.S. Congress
  and the home of the U.S. Copyright Office. The Library publishes a suite of public APIs that expose its catalog, digital
  collections, historic newspapers, and legislative information.
type: Index
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
position: Producer
access: Public
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/library-of-congress.png
tags:
- Cultural Heritage
- Federal-Government
- Library
- Legislative
- Newspapers
- Search
tags_raw:
- Cultural Heritage
- Federal Government
- Library
- Legislative
- Newspapers
- Search
created: '2024-01-01'
modified: '2026-05-19'
url: https://raw.githubusercontent.com/api-evangelist/library-of-congress/refs/heads/main/apis.yml
specificationVersion: '0.23'
apis:
- aid: library-of-congress:library-of-congress-bills-api
  name: Library of Congress Bills API
  description: The Bills API from Library of Congress — 3 operation(s) for bills.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Bills
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-bills-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-collections-api
  name: Library of Congress Collections API
  description: The Collections API from Library of Congress — 2 operation(s) for collections.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Collection
  tags_raw:
  - Collections
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-collections-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-committees-api
  name: Library of Congress Committees API
  description: The Committees API from Library of Congress — 1 operation(s) for committees.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Committees
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-committees-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-congressional-record-api
  name: Library of Congress Congressional Record API
  description: The Congressional Record API from Library of Congress — 1 operation(s) for congressional record.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Congressional Record
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-congressional-record-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-issues-api
  name: Library of Congress Issues API
  description: The Issues API from Library of Congress — 1 operation(s) for issues.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Issues
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-issues-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-items-api
  name: Library of Congress Items API
  description: The Items API from Library of Congress — 1 operation(s) for items.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Item
  tags_raw:
  - Items
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-items-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-laws-api
  name: Library of Congress Laws API
  description: The Laws API from Library of Congress — 1 operation(s) for laws.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Laws
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-laws-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-members-api
  name: Library of Congress Members API
  description: The Members API from Library of Congress — 2 operation(s) for members.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Members
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-members-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-pages-api
  name: Library of Congress Pages API
  description: The Pages API from Library of Congress — 1 operation(s) for pages.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Pages
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-pages-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-resources-api
  name: Library of Congress Resources API
  description: The Resources API from Library of Congress — 1 operation(s) for resources.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Resources
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-resources-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-search-api
  name: Library of Congress Search API
  description: The Search API from Library of Congress — 1 operation(s) for search.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Search
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-search-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: library-of-congress:library-of-congress-titles-api
  name: Library of Congress Titles API
  description: The Titles API from Library of Congress — 3 operation(s) for titles.
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - Titles
  properties:
  - type: OpenAPI
    url: openapi/library-of-congress-titles-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Reference
    url: https://www.loc.gov/apis/json-and-yaml/requests/
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  - type: Documentation
    url: https://github.com/LibraryOfCongress/api.congress.gov/
  - type: Signup
    url: https://api.congress.gov/sign-up/
common:
- type: AgenticAccess
  url: agentic-access/library-of-congress-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/library-of-congress-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/library-of-congress-domain-security.yml
- type: Authentication
  url: authentication/library-of-congress-authentication.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/library-of-congress
- type: Website
  url: https://www.loc.gov/
- type: Documentation
  url: https://www.loc.gov/apis/
- type: Reference
  url: https://www.loc.gov/apis/json-and-yaml-responses/
- type: GitHubOrganization
  url: https://github.com/LibraryOfCongress
- type: Integrations
  url: https://www.loc.gov/apps
- url: https://blogs.loc.gov/loc/feed/
  type: Blog
integrations:
- name: Facebook
- name: Copy Link
- name: Library of Congress Facebook
- name: Library of Congress X
- name: Library of Congress YouTube
- name: Library of Congress Pinterest
- name: Library of Congress Flickr
- name: Library of Congress Instagram
- name: Library of Congress iTunesU
- name: Library of Congress LinkedIn
- name: Email
- name: Congress.gov
- name: United States Copyright Office
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com