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.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles Library of Congress the way a machine reads it — 22 machine-readable artifacts across 12 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Library of Congress scores 40.4/100 (thin), with a separate agent-readiness read of 48/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Library of Congress
Each block below is one kind of artifact we hold for Library of Congress. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 12
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Library of Congress Bills API
The Bills API from Library of Congress — 3 operation(s) for bills.
Library of Congress Collections API
The Collections API from Library of Congress — 2 operation(s) for collections.
Library of Congress Committees API
The Committees API from Library of Congress — 1 operation(s) for committees.
Library of Congress Congressional Record API
The Congressional Record API from Library of Congress — 1 operation(s) for congressional record.
Library of Congress Issues API
The Issues API from Library of Congress — 1 operation(s) for issues.
Library of Congress Items API
The Items API from Library of Congress — 1 operation(s) for items.
Library of Congress Laws API
The Laws API from Library of Congress — 1 operation(s) for laws.
Library of Congress Members API
The Members API from Library of Congress — 2 operation(s) for members.
Library of Congress Pages API
The Pages API from Library of Congress — 1 operation(s) for pages.
Library of Congress Resources API
The Resources API from Library of Congress — 1 operation(s) for resources.
Library of Congress Search API
The Search API from Library of Congress — 1 operation(s) for search.
Library of Congress Titles API
The Titles API from Library of Congress — 3 operation(s) for titles.
Scroll within the panel for all 12 ·
Open Collections 3
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Library of Congress Chronicling America API
OPEN COLLECTIONLibrary of Congress Congress.gov API
OPEN COLLECTIONLibrary of Congress loc.gov JSON API
OPEN COLLECTIONPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Library Of Congress Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Security Posture 3
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Library of Congress — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 3
Authentication, authorization, and security posture
Company 3
The organization behind the API
← All providers · Data indexed from github.com/api-evangelist/library-of-congress · machine-readable index on apis.io