ISBNdb.com

[5] In July 2005 ISBNdb.com released an XML-based API, which enables users to access all of the book information in real-time.

[8] ISBNdb aggregates information for its database from hundreds of libraries, publishers, merchants, and other sources around the globe.

[11] ISBNdb offers up to 19 data points per book including ISBN10, ISBN13, title, author, publication date, publisher, binding, pages, list price, cover image, language, edition, format, synopsis, and dimensions.

[14] ISBNdb provides free limited book data to unregistered users via a web interface.

[15] Registered users can access full book data with the help of a web interface and API, based on a subscription.