Library of Congress JSON API
excluded Legislative · Tier 3 · API · Library of Congress
Official site (opens in a new tab) · All sources
What this source is
The loc.gov JSON/YAML API over the Library's collections, including Prints & Photographs — an archive of record with per-item rights variation, not a publication stream.
Identity and registry record
- Registry id
loc-api- Agency / parent organization
- Library of Congress
- Branch
- legislative
- Type
- API
- Status
- evaluated-excluded
- Tier
- 3
- URL (home)
- https://www.loc.gov/apis/ (opens in a new tab)
- Registered
- 2026-07-28
- Registry notes
- Evaluated 2026-07-28: keyless documented API with enforced rate limits (429s under load), but archival; rights vary per item (LoC holdings are not uniformly public domain). Current legislative-data needs are met by api.congress.gov. Revisit for historical features only.
How we ingest it
- Channel
- API
- Method
- Not applicable to the daily flow — archive, not news-flow.
- Request budget
- the agency class: at most 1,500 requests per day shared across every agency web source, counted from the fetch log (failed requests count too)
- Politeness
- robots.txt is honored as observed — including each host's crawl-delay, exactly — and every request identifies itself as fapd/0.1 (Free Agentic Publication Digester; +https://fapd.info/bot.html; contact: hustleyourcity@gmail.com); a refusal is recorded, never evaded
- Capture and hash
- captured raw content is hashed (SHA-256) into the day's committed provenance manifest, hash-chained day to day (PROVENANCE.md)
Ingestion health
Not ingested: the registry status of this source is evaluated-excluded.
Ingestion statistics
These figures describe this project's ingestion of this source — items we recorded and requests we made — and nothing else. They are not a measurement of the publisher.
Not ingested: the registry status of this source is evaluated-excluded. Ingestion statistics are measured for active sources only.
All time
No requests to www.loc.gov are recorded in the request log.
Last 30 days, day by day
No requests and no items were recorded in the last 30 days, so there is nothing to chart.