API guides/Reference data
Open Library search and ISBN lookup. Free, no key. Be polite with rate and cache covers.
1 provider · 3 min · Limits change — verify before you ship
Reference data
Open Library is Internet Archive’s book catalogue. Good for covers, titles, and ISBN checks. Not a commercial product database like a paid ISBN agency feed.
GET https://openlibrary.org/isbn/{isbn}.json
HTTPS
Yes
API key
No key
CORS
Usually yes
Use
Free tier
Limits. No official unlimited SLA. Cache. Avoid tight loops and bulk harvest on the public site.
Commercial. Follow Open Library / Internet Archive terms.
Note. Search: https://openlibrary.org/search.json?q=… Covers use a separate covers.openlibrary.org URL pattern.
curl -sS "https://openlibrary.org/isbn/9780140328721.json"PureDevKit does not host or proxy these APIs. Pricing, rate limits, CORS, authentication, and JSON shapes can change without notice. Always confirm the current rules on the provider’s official documentation before you ship.