Open Publication Distribution System

The Open Publication Distribution System (OPDS) catalog format is a syndication format for electronic publications based on Atom and HTTP. OPDS catalogs enable the aggregation, distribution, discovery, and acquisition of electronic publications. OPDS catalogs use existing or emergent open standards and conventions, with a priority on simplicity.

The Open Publication Distribution System specification is prepared by an informal grouping of partners, combining Internet Archive, O'Reilly Media, Feedbooks, OLPC, and others.

History
OPDS is based on the initial work done by Lexcycle, the company behind Stanza, an eBook reader application for iOS. All revisions of the specification were produced by an informal group organized around an open mailing list.

OPDS software
Many e-readers or e-book reading applications support importing books from an OPDS catalog. E-book management applications such as Calibre also often include OPDS server software to make an e-book collection available through an OPDS catalog.

Example of OPDS 1.1 content
An example of an acquisition feed in OPDS:

OPDS catalogs
Dozens of OPDS catalogs are available online, and in many different languages.

Many users of OPDS also create their own OPDS catalog, as a way to access their ebooks from any device.

Developers implementing an OPDS catalog usually use the Feedbooks catalog as an example of a fully featured catalog. An OPDS validator is also available to test OPDS feeds.