Open Library now supports the Read API for turning book identifiers (ISBN, etc.) into direct links links to our online eBooks.
You can use this API to add read/borrow links to your library catalog search results.
Here's an example using the Evergreen ILS (from the Laurentian University catalog).
(Look for the 'Borrow online' links on the right. Note that you'll need a Laurentian library card to get to these, in this example.)
The Internet Archive is providing MARC records for our borrowable books. 105,852 so far! We've added new 856 fields to the records, with links to Open Library and Internet Archive pages for the books.
The 856 fields usually have an Open Library link. Display this to your users, as this is where they'll go to borrow books. The Internet Archive may have more information about the scan itself, but can't be (directly) used to borrow books.
To support remote users, you may need to use EZProxy with the links in the 856 fields. Use it with the Open Library links, but don't proxy the Archive.org links, as this interferes with the book authentication code.
Note that some books may not have an Open Library link. These books aren't borrowable; we're hoping to fix this soon.