Open Library

Books, book covers and related data

Open Library is an open, editable library catalog with the goal of having a page for every book ever published. The API provides free access to book metadata, cover images in multiple sizes, author information, and subject data — all without authentication. It's backed by the Internet Archive. For OpenClaw agents, Open Library is a great zero-auth alternative to Google Books for book lookups. The covers API is particularly useful — you can fetch cover images by ISBN, OLID, or other identifiers in S/M/L sizes. Ideal for enriching reading lists, building book recommendation bots, or adding cover art to Notion databases.

Tags: data, books

Category: Books

Use Cases

  • Fetch book cover images by ISBN for enriching Notion databases or blog posts
  • Build a 'what is this book about' skill that returns Open Library metadata
  • Cross-reference with Google Books for more complete book data

Tips

  • Use the ISBN endpoint for the most reliable lookups: /isbn/{isbn}.json
  • The covers API is extremely fast and doesn't count against rate limits
  • Add .json to any Open Library URL to get the JSON representation

Known Issues & Gotchas

  • CORS is not supported — server-side requests only (fine for OpenClaw skills)
  • Rate limits are informal but real — hammering the API will get you throttled
  • Some book records are community-edited and may have inconsistent data quality

Frequently Asked Questions

Does Open Library require authentication?

No. All read endpoints (search, books, covers, authors) are fully open with no API key needed.

How do I get cover images from Open Library?

Use the covers API: https://covers.openlibrary.org/b/isbn/{ISBN}-{SIZE}.jpg where SIZE is S, M, or L. Works for OLIDs and other identifiers too.

Is the data as comprehensive as Google Books?

Open Library has excellent coverage for older and public domain works. For newer titles, Google Books may have more complete metadata. Using both together gives the best coverage.