# Library of Congress

**Canonical:** https://apis.io/providers/loc/  
**Website:** https://www.loc.gov  
**APIs profiled:** 25

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.

## Kin Score — 40.2 / 100 (developing)

Scored 2026-08-20 under rubric 0.12.0. Trend: flat (+0.0 from 40.2).

| Facet | Score |
|---|---|
| Discoverability | 74.1 |
| Contract Quality | 55.8 |
| Governance | 9.8 |
| Contract Governance | 9.8 |
| Operational Transparency | 5.3 |
| Developer Ergonomics | 23.8 |
| Commercial Clarity | 50.0 |
| Access Clarity | 50.0 |

Regulatory layer — **Education & Research**: 42.6 (matched via tags).

## Agent readiness — 38.3 (agent-ready)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | na |
| MCP Server | no |
| Auth Clarity | yes |
| Idempotency | na |
| Error Semantics | no |
| OpenAPI Examples | partial |
| Rate Limit Signal | documented |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | na |

## Access

Free · Open access — onboarding: open, pricing: free, trial: no (confidence: high).

## APIs (25)

- **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

## Agentic access (1)

- **Loc Agentic Access** — 121 operations

## Security (3)

- **Loc Authentication** — apiKey · 1 scheme
- **Loc Domain Security** — TLSv1.3 · HSTS · DNSSEC · DMARC
- **Loc Vulnerability Disclosure** — security.txt · contact published

## Plans (1)

- **Loc Plans Pricing**

## Tags

Library, Government, Congress, Legislative Data, Digital Collections, Newspapers, Maps, Bibliographic Records, Historical Documents

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/loc/). Scores are computed from the provider's own public artifacts under a published rubric.