Open Library API
Books, authors, covers, and full-text search across 20+ million records from the Internet Archive's Open Library project. Covers API serves book cover images by ISBN.
🟢 Online · 1091 ms
97.5%
Free (courtesy rate limits), no key, no credit card
No key required
Free alternatives (live ranking)
- Free Dictionary API — 🟢 Online · Unlimited (fair use), no key, no credit card
- ipify — 🟢 Online · Unlimited, no key, no credit card
- DiceBear Avatars — 🟢 Online · Unlimited (fair use), no key, no credit card
Compare Open Library API with…
- Open Library API vs Free Dictionary API — Unlimited (fair use), no key, no credit card
- Open Library API vs ipify — Unlimited, no key, no credit card
- Open Library API vs DiceBear Avatars — Unlimited (fair use), no key, no credit card
Paid alternatives
- Google Books API — free with API key
- ISBNdb — from $14.95/mo
Frequently Asked Questions
Does Open Library API require an API key?
No, Open Library API is freely accessible without registration or an API key.
What is Open Library API's free tier?
Free (courtesy rate limits), no key, no credit card
Is Open Library API currently online?
We check Open Library API every hour. The current status is shown at the top of this page. You can also see the 30-day uptime history in the chart above.
Implementation notes
When to use Open Library API
Open Library is the Internet Archive's open books database — 20+ million book records, author data, subjects, and cover images, all accessible without a key. Three APIs matter: Search (`/search.json?q=`), Works/Editions (structured metadata by ID or ISBN), and Covers (`covers.openlibrary.org/b/isbn/{isbn}-M.jpg` — hotlinkable book cover images by ISBN). Use it for reading trackers, book recommendation apps, library tools, and anywhere you need 'ISBN in, metadata + cover out' without Google Books' key management.
Common pitfalls
- The Search API is powerful but slow (500ms-2s) and returns large payloads. Use the `fields` parameter to request only what you need (`fields=title,author_name,isbn,cover_i`) — it cuts response size by 10x and roughly halves latency.
- Cover images by ISBN return a 1x1 transparent pixel when no cover exists, NOT a 404. Check the Content-Length or use `?default=false` to get a proper 404 you can catch and replace with your placeholder.
- Courtesy rate limit is roughly 100 requests per 5 minutes per IP. Bulk enrichment jobs (matching a big CSV of ISBNs) should throttle to ~1 req/3s or use the monthly data dumps instead — the full catalog is downloadable for free.
- Data quality is crowdsourced: duplicate works, missing page counts, and inconsistent author name forms are common. Treat it as 'very good, occasionally messy' — normalize author names before displaying grouped results.
Quick start (bash)
curl "https://openlibrary.org/search.json?q=the+hobbit&fields=title,author_name,first_publish_year,isbn&limit=3"Embed this badge
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