Library of Congress website screenshot

Library of Congress

The Library of Congress is the largest library in the world and the research arm of the US Congress. It provides REST APIs for accessing digitized collections, Congress.gov legislative data, bibliographic records, historic newspapers via Chronicling America, maps, photographs, manuscripts, and historical government documents. The loc.gov JSON API requires no authentication, while the Congress.gov API requires a free API key.

Library of Congress publishes 24 APIs on the APIs.io network, including amendments API, bill API, bound-congressional-record API, and 21 more. Tagged areas include Library, Government, Congress, Legislative Data, and Digital Collections.

The Library of Congress catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Library of Congress’ developer surface includes authentication, documentation, engineering blog, pricing, and 11 more developer resources.

🌐 Visit website 📡 Source on GitHub
45.7/100 developing ▼ -6.1 Agent 34/100 agent aware Full breakdown ↓
scored 2026-07-28 · rubric v0.6
AccessFreeOpen⚡ Free to try
25 APIs
LibraryGovernmentCongressLegislative DataDigital CollectionsNewspapersMapsBibliographic RecordsHistorical Documents

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6
Composite quality — 45.7/100 · developing
Contract Quality 14.8 / 25
Developer Ergonomics 4.3 / 20
Commercial Clarity 10.0 / 20
Operational Transparency 2.7 / 13
Governance 7.0 / 12
Discoverability 7.4 / 10
Agent readiness — 34/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 7 / 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 0 / 4
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/loc: 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 25

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

Chronicling America API

The Chronicling America API provides access to the historic American newspapers collection digitized by the Library of Congress and its partners. Endpoints allow searching and r...

Library of Congress amendments API

Returns amendment data from the API

Library of Congress bill API

Returns bill data from the API

Library of Congress bound-congressional-record API

Returns bound Congressional Record data from the API

Library of Congress collections API

Browse and access digital collections

Library of Congress committee API

Returns committee data from the API

Library of Congress committee-meeting API

Returns committee meeting data from the API

Library of Congress committee-print API

Returns committee print data from the API

Library of Congress committee-report API

Returns committee report data from the API

Library of Congress congress API

Returns congress and congressional sessions data from the API

Library of Congress congressional-record API

Returns Congressional Record data from the API

Library of Congress crsreport API

Returns Congressional Research Service (CRS) report data from the API

Library of Congress daily-congressional-record API

Returns daily Congressional Record data from the API

Library of Congress formats API

Browse items by format type

Library of Congress hearing API

Returns hearing data from the API

Library of Congress house-communication API

Returns House communication data from the API

Library of Congress house-requirement API

Returns House requirement data from the API

Library of Congress house-vote API

[BETA] Returns House of Representatives roll call vote data from the API

Library of Congress items API

Access individual item details

Library of Congress member API

Returns member data from the API

Library of Congress nomination API

Returns nomination data from the API

Library of Congress search API

Search across all loc.gov digital collections

Library of Congress senate-communication API

Returns Senate communication data from the API

Library of Congress summaries API

Returns summaries data from the API

Library of Congress treaty API

Returns treaty data from the API

Scroll for all 25

Pricing Plans 1

Published pricing tiers and plan structures.

Loc Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Loc Rate Limits

0 limits

RATE LIMITS

FinOps 1

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

Loc Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Loc Context

11 classes · 26 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Library of Congress API Rules

6 rules · 3 warnings 3 info

SPECTRAL

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

Congress.gov API Schemas

0 properties

JSON SCHEMA

Examples 1

Example request and response payloads for these APIs.

Loc Congress Gov Examples

6 fields

EXAMPLE

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Loc Authentication

apiKey · 1 scheme

SECURITY

Loc Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Loc Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Loc Agentic Access

121 operations

121 operations · 0 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrg
GitHubOrg

Access & Security 3

Authentication, authorization, and security posture

VulnerabilityDisclosure
VulnerabilityDisclosure
 DomainSecurity
DomainSecurity
 Authentication
Authentication

Operate 2

Status, limits, changes, and where to get help

StatusPage
StatusPage
 RateLimits
RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

Pricing
Pricing
 Plans
Plans
 FinOps
FinOps

Company 3

The organization behind the API

Website
Website
 LinkedIn
LinkedIn
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

X
X

Source (apis.yml)

apis.yml Raw ↑ 
aid: loc
name: Library of Congress
description: The Library of Congress is the largest library in the world and the research arm of the US Congress. It provides
  REST APIs for accessing digitized collections, Congress.gov legislative data, bibliographic records, historic newspapers
  via Chronicling America, maps, photographs, manuscripts, and historical government documents. The loc.gov JSON API requires
  no authentication, while the Congress.gov API requires a free API key.
accessModel:
  pricing: free
  onboarding: open
  trial: false
  try_now: true
  public: true
  label: Free · Open access
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/loc.png
url: https://raw.githubusercontent.com/api-evangelist/loc/refs/heads/main/apis.yml
created: '2026-06-13'
modified: '2026-06-13'
specificationVersion: '0.19'
type: Index
tags:
- Library
- Government
- Congress
- Legislative Data
- Digital Collections
- Newspapers
- Maps
- Bibliographic Records
- Historical Documents
apis:
- name: Chronicling America API
  description: The Chronicling America API provides access to the historic American newspapers collection digitized by the
    Library of Congress and its partners. Endpoints allow searching and retrieving pages, titles, batches, and OCR text. No
    authentication is required.
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  humanURL: https://chroniclingamerica.loc.gov/about/api/
  baseURL: https://chroniclingamerica.loc.gov
  tags:
  - Newspapers
  - Historical
  - Digitized
  - Search
  - OCR
  properties:
  - type: Documentation
    url: https://chroniclingamerica.loc.gov/about/api/
  contact:
  - FN: Library of Congress
    url: https://www.loc.gov/about/contact-us/
- aid: loc:loc-amendments-api
  name: Library of Congress amendments API
  description: Returns amendment data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - amendments
  properties:
  - type: OpenAPI
    url: openapi/loc-amendments-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-bill-api
  name: Library of Congress bill API
  description: Returns bill data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - bill
  properties:
  - type: OpenAPI
    url: openapi/loc-bill-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-bound-congressional-record-api
  name: Library of Congress bound-congressional-record API
  description: Returns bound Congressional Record data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - bound-congressional-record
  properties:
  - type: OpenAPI
    url: openapi/loc-bound-congressional-record-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-collections-api
  name: Library of Congress collections API
  description: Browse and access digital collections
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - collections
  properties:
  - type: OpenAPI
    url: openapi/loc-collections-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-committee-api
  name: Library of Congress committee API
  description: Returns committee data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - committee
  properties:
  - type: OpenAPI
    url: openapi/loc-committee-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-committee-meeting-api
  name: Library of Congress committee-meeting API
  description: Returns committee meeting data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - committee-meeting
  properties:
  - type: OpenAPI
    url: openapi/loc-committee-meeting-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-committee-print-api
  name: Library of Congress committee-print API
  description: Returns committee print data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - committee-print
  properties:
  - type: OpenAPI
    url: openapi/loc-committee-print-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-committee-report-api
  name: Library of Congress committee-report API
  description: Returns committee report data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - committee-report
  properties:
  - type: OpenAPI
    url: openapi/loc-committee-report-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-congress-api
  name: Library of Congress congress API
  description: Returns congress and congressional sessions data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - congress
  properties:
  - type: OpenAPI
    url: openapi/loc-congress-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-congressional-record-api
  name: Library of Congress congressional-record API
  description: Returns Congressional Record data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - congressional-record
  properties:
  - type: OpenAPI
    url: openapi/loc-congressional-record-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-crsreport-api
  name: Library of Congress crsreport API
  description: Returns Congressional Research Service (CRS) report data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - crsreport
  properties:
  - type: OpenAPI
    url: openapi/loc-crsreport-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-daily-congressional-record-api
  name: Library of Congress daily-congressional-record API
  description: Returns daily Congressional Record data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - daily-congressional-record
  properties:
  - type: OpenAPI
    url: openapi/loc-daily-congressional-record-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-formats-api
  name: Library of Congress formats API
  description: Browse items by format type
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - formats
  properties:
  - type: OpenAPI
    url: openapi/loc-formats-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-hearing-api
  name: Library of Congress hearing API
  description: Returns hearing data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - hearing
  properties:
  - type: OpenAPI
    url: openapi/loc-hearing-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-house-communication-api
  name: Library of Congress house-communication API
  description: Returns House communication data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - house-communication
  properties:
  - type: OpenAPI
    url: openapi/loc-house-communication-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-house-requirement-api
  name: Library of Congress house-requirement API
  description: Returns House requirement data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - house-requirement
  properties:
  - type: OpenAPI
    url: openapi/loc-house-requirement-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-house-vote-api
  name: Library of Congress house-vote API
  description: '[BETA] Returns House of Representatives roll call vote data from the API'
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - house-vote
  properties:
  - type: OpenAPI
    url: openapi/loc-house-vote-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-items-api
  name: Library of Congress items API
  description: Access individual item details
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - items
  properties:
  - type: OpenAPI
    url: openapi/loc-items-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-member-api
  name: Library of Congress member API
  description: Returns member data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - member
  properties:
  - type: OpenAPI
    url: openapi/loc-member-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-nomination-api
  name: Library of Congress nomination API
  description: Returns nomination data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - nomination
  properties:
  - type: OpenAPI
    url: openapi/loc-nomination-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-search-api
  name: Library of Congress search API
  description: Search across all loc.gov digital collections
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - search
  properties:
  - type: OpenAPI
    url: openapi/loc-search-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-senate-communication-api
  name: Library of Congress senate-communication API
  description: Returns Senate communication data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - senate-communication
  properties:
  - type: OpenAPI
    url: openapi/loc-senate-communication-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-summaries-api
  name: Library of Congress summaries API
  description: Returns summaries data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - summaries
  properties:
  - type: OpenAPI
    url: openapi/loc-summaries-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
- aid: loc:loc-treaty-api
  name: Library of Congress treaty API
  description: Returns treaty data from the API
  humanURL: https://www.loc.gov/apis/json-and-yaml/
  baseURL: https://www.loc.gov
  tags:
  - treaty
  properties:
  - type: OpenAPI
    url: openapi/loc-treaty-api-openapi.yml
  - type: Documentation
    url: https://www.loc.gov/apis/json-and-yaml/
  - type: Documentation
    url: https://api.congress.gov/
  - type: GitHubRepository
    url: https://github.com/LibraryOfCongress/api.congress.gov
  - type: Signup
    url: https://api.congress.gov/sign-up/
common:
- type: AgenticAccess
  url: agentic-access/loc-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/loc-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/loc-domain-security.yml
- type: Authentication
  url: authentication/loc-authentication.yml
- type: Website
  url: https://www.loc.gov
- type: Documentation
  url: https://www.loc.gov/apis/
- type: GitHubOrg
  url: https://github.com/LibraryOfCongress
- type: LinkedIn
  url: https://www.linkedin.com/company/library-of-congress
- type: Blog
  url: https://blogs.loc.gov/thesignal/
- type: Pricing
  url: https://www.loc.gov/apis/
- type: StatusPage
  url: https://uptime.com/upstatus/loc.gov
- type: X
  url: https://twitter.com/librarycongress
- type: Plans
  url: plans/loc-plans-pricing.yml
- type: RateLimits
  url: rate-limits/loc-rate-limits.yml
- type: FinOps
  url: finops/loc-finops.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com