Open Library

← back to the index

Category: Knowledge · Auth: none · Status on 2026-10-05: OK (HTTP 200) · 713 ms

Open Library API is a free knowledge API that needs no key. On 2026-10-05 00:08 UTC our sweep found it live, answering HTTP 200 in 713 ms.

What it gives you

Book metadata by ISBN/title/author, covers, subjects. Wikipedia-for-books.

Auth and limits

These auth and limit details come from our curated field guide, as the provider documented them when the entry was written or last corrected. The daily sweep checks that the API answers; it does not re-verify the provider's limits, so check the documentation before relying on a number.

Example request

This is the exact probe the sentinel runs each sweep — one read-only GET. The result above carries the date it was measured:

curl -s 'https://openlibrary.org/isbn/9780140328721.json'

Example output

Captured 2026-10-05 00:08 UTC (application/json, first 400 chars):

{"identifiers": {"goodreads": ["1507552"], "librarything": ["6446"]}, "title": "Fantastic Mr. Fox", "authors": [{"key": "/authors/OL34184A"}], "publish_date": "October 1, 1988", "publishers": ["Puffin"], "covers": [15152634, 8739161, -1], "contributions": ["Tony Ross (Illustrator)"], "languages": [{"key": "/languages/eng"}], "source_records": ["promise:bwb_daily_pallets_2021-05-13:KP-140-654", "ia

How the sentinel checks it

Once per sweep the sentinel sends one read-only GET to the URL above, with a descriptive user-agent and a 10-second timeout, and records the HTTP status, the round-trip time, the content type and the first few hundred characters of the response. Only a timeout is re-probed, once, with a 45-second ceiling. The status measured on 2026-10-05, OK, means the probe got a 2xx or 3xx response within the 10-second timeout. One reading is one sweep from one shared network address, not a guarantee of uptime: a per-IP rate limit can read as an error on our side.

Get this from an agent

The same measurement is in the api-health.json feed, dated by its generated_at; filter results on name == "Open Library". An MCP client can call the check_api_health tool at /mcp with {"api": "Open Library"}; it answers from the same feed.

Other free knowledge APIs checked 2026-10-05

Checked 2026-10-05 00:08 UTC by the AI Deals Sentinel. Machine-readable: api-health.json.