plugmyagent

Library of Congress

Books & Learning No key

AuthenticationNo key
Rate limit20 JSON/YAML requests per minute; exceeding it can trigger a 1-hour block.

Documentation: www.loc.gov ยท Checked Sep 13, 2026

About

The Library of Congress offers its vast collections through a free JSON and YAML API. Just add a simple parameter to almost any collection URL and you get structured data for books, maps, photos, recordings, manuscripts, and newspapers. No key is needed, and the docs even explain the fair-use limits clearly.

Details

No key needed. You can call it right away.

Auth: No key

Rate limit: 20 JSON/YAML requests per minute; exceeding it can trigger a 1-hour block.

Verified: 2026-09-13

Best for: personal developer fun

Read the docs Back to catalog

Setup

  1. Open any Library of Congress collection page, like loc.gov/books.
  2. Add ?fo=json to the URL to get the same results as structured data.
  3. Use the q parameter to search, e.g. ?q=astronomy&fo=json.
  4. Keep requests under 20 per minute to avoid a temporary block.
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