Open Library

Overview

Open Library (a project of the Internet Archive) exposes its catalog of 40+ million books as a free, keyless REST API: full-text search, book/author/work records, covers, and editions data. It’s the go-to free data source for book-related apps.

Quick Start

Search books:

curl "https://openlibrary.org/search.json?q=harry+potter&limit=3"

Get a work’s details (note: some keys are redirects — follow them):

curl "https://openlibrary.org/works/OL45883W.json"

Get book cover images (no key needed):

https://covers.openlibrary.org/b/isbn/0451526538-S.jpg   # small
https://covers.openlibrary.org/b/isbn/0451526538-M.jpg   # medium
https://covers.openlibrary.org/b/isbn/0451526538-L.jpg   # large

Fetch an edition by ISBN:

curl "https://openlibrary.org/isbn/0451526538.json"

What’s in the data

• Search results: title, author(s), first publish year, ISBNs, cover IDs, edition count
• Work/edition records: full metadata, descriptions, subjects, links
• Author records: bio, birth/death dates, works list
• Covers API: by ISBN, OCLC, LCCN, or Open Library ID

Authentication

None — keyless and open.

Rate Limits & Notes

• Free, with a reasonable request budget (the docs ask for a conservative rate and no aggressive bulk scraping).
• search.json supports q, title, author, subject, limit/offset, fields (choose only what you need — keeps responses small).
• Some work keys return redirects ({"type": "/type/redirect"}) — follow the location field.
• The covers CDN is fast and hotlink-friendly for production use.

FAQ

Is Open Library free? Yes — free, keyless, and open (Internet Archive project).

Can I use the cover images in my app? Yes — the covers API is designed for hotlinking at small/medium/large sizes.

Can I call it from the browser? CORS isn’t reliably advertised — for client-side apps, route through your own server if you hit issues.