EPUBCheck plays a significant role within the ebook production process, checking EPUB files against the specification to ensure they validate. As the EPUB specification has evolved over time it is important that the tools we use to create and validate EPUB files are kept up to date. Many retailers require EPUB files to have been validated by EPUBCheck.

The Publishing Business Group at W3C put out a request for proposals to update EPUBCheck and, following a competitive selection process, the DAISY Consortium was selected to perform the update to:

  • Bring EPUBCheck in sync with the dynamically evolving core web specs of HTML, CSS, and SVG and also with the current version of EPUB 3
  • Fully support the EPUB Accessibility Guidelines, making sure that your products are usable for everyone
  • Add new features, such as HTML validation (in coordination with the W3C validation services) and a better check of media overlays
  • Offer better service to the publishing industry with a faster response to bug reports and feature request.

This work is being funded through donations from organizations which use the EPUBCheck tool, and while there are different sponsorship levels, any amount of donation is welcome to help support this effort to update and overhaul EPUBCheck. Full details are available at the Publishing@W3C fundraising page.

Current Status – EPUBCheck Version 4.2.2

The latest production-ready release of EPUBCheck took place in July 2019, providing complete support for checking conformance to the EPUB 3.2 family of specifications.

Version 4.2.2 is a maintenance release which:

  • reverts the toc and page-list navigation order check to a mere WARNING (it was previously an ERROR), following the recent EPUB CG discussion.
  • includes new translations, notably for Traditional Chinese.

Further Information

For more detailed information on updates and version releases please visit the EPUBCheck development site.