Open Publication Distribution System (OPDS)

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.
— Wikipedia

I have OPDS OPDS server, to host my fiction books.