EpubCheck is a tool to validate EPUB files. It is also able to extract technical characteristics and embedded metadata from an EPUB file. Both the EPUB 2 and EPUB 3 formats are supported. It can detect many types of errors in EPUB. OCF container structure, OPF and OPS mark-up, and internal reference consistency are checked. EpubCheck can be run as a standalone command-line tool or used as a Java library. Development of this tool is supported by the International Digital Publishing Forum (IDPF), which also publishes the EPUB standards. Most of the EpubCheck functionality comes from the schema validation tool Jing and schemas that were developed by IDPF and DAISY. Initial EpubCheck development was largely done at Adobe Systems.
Authors and contributors to EpubCheck include:
- Peter Sorotokin
- Garth Conboy
- Markus Gylling
- Piotr Kula
- Paul Norton
- Jessica Hekman
- Liza Daly
- George Bina
- Bogdan Iordache
- Romain Deltour
- Thomas Ledoux
- Tobias Fischer
- Steve Antoch
- Arwen Pond
- Masayoshi Takahashi
- Satoshi Kojima
 Documentation and user support
Using EPubCheck as command line tool, all detected errors are simply printed to stderr output stream. There is no native graphical user interface (GUI) for the tool. However, there are some third-party apps offering a GUI for Windows/Mac/Linux platforms: • pagina EPUB-Checker for Windows / Mac / Linux • ePub Checker for iPad/iPod/iPhone (iTunes Store App)
- EPubCheck is a command line tool that can be run on any operating system (OS).
- EPubCheck can be used as part of Java library.
- Build tool require Java Development Kit JDK (1.6 or above)
 Online version of EpubCheck
- Documentation on how to use or how to contribute is available on the EpubCheck wiki.
- Technical discussions are hosted on the EpubCheck Google Group.
 User Experiences
 EPubCheck standard on Smashwors publishing
Self-publishing site, Smashwords, requires author to pass EPubCheck in order to get their publication to Apple Bookstore HOW TO FIX EPUBCHECK ERRORS
 Development Activity
For tool updates and development, check https://github.com/IDPF/epubcheck
 Release Feed
Below the last 3 release feeds: Failed to load RSS feed from https://github.com/IDPF/epubcheck/releases.atom: Error fetching URL: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version
 Activity Feed
Below the last 5 commits: Failed to load RSS feed from https://github.com/IDPF/epubcheck/commits/master.atom: Error fetching URL: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version