IDPF

International Digital Publishing Forum (IDPF) was a nonprofit standards organization established in 2000 to develop and promote open specifications for digital publishing and e-books. It brought together publishers, distributors, technology providers, and libraries to harmonize formats, metadata, and workflows for digital publications.

IDPF’s most widely known achievement was the EPUB format, which defines a packaging standard and a content model designed for portable, accessible e-books. EPUB typically uses the Open Packaging Format (OCF) to containerize content and the Open Packaging Format (OPF) for describing the publication’s manifest, spine, and metadata, with content based on HTML or XHTML, CSS, and multimedia where appropriate. The format supports both reflowable text and fixed layouts, making it suitable for a range of devices and reading experiences. In addition to EPUB, IDPF worked on related guidelines and specifications affecting accessibility, metadata, licensing, and interchange practices within digital publishing.

In 2016, the IDPF merged with the World Wide Web Consortium (W3C), and the organization was dissolved. Its standards activities and ongoing work on EPUB were continued within the W3C ecosystem, notably under publishing-related initiatives. The IDPF’s legacy lies in standardizing interoperable digital publishing formats that influenced e-book ecosystems, libraries, and content distribution practices across platforms.