Snowflower EPUB Validator Overview

The Snowflower EPUB Validator can easily check the problem of EPUB format e-books.

Even if you apply for registration of an e-book created by you to the store, even if you do not pass the review due to the problem of the EPUB file, or if the review goes through, the purchaser’s e-book reader may display problems. The Snowflower EPUB Validator automatically and quickly finds problems that are hard to find by visual inspection and reports it clearly. If you check the EPUB file for problems before registering to the store, It is possible to suppress the occurrence of problems.


  • Supports specification of EPUB 2 & 3

  • Easy operation of drag & drop of EPUB file is possible

  • EPUB problems are reported at three severity levels: fatal, error, and warning.

  • Work offline without uploading EPUB files to external server.

  • IDPF EpubCheck 5.1.0 built-in


    “EpubCheck” is developed by IDPF(The International Digital Publishing Forum) It is a command line tool for checking EPUB files.

Validity check specification

The Snowflower EPUB Validator supports validation against the following EPUB specifications:

  • EPUB 3.3

  • EPUB Dictionaries and Glossaries 1.0

  • EPUB Indexes 1.0

  • EPUB Multiple-Rendition Publications 1.0

  • EPUB Previews 1.0

  • EPUB Region-Based Navigation 1.0

It also provides an early implementation of checks for the following draft specifications:

  • EPUB 3 EDUPUB Profile

  • EPUB Distributable Objects 1.0

  • EPUB Scriptable Components Packaging and Integration 1.0

Validation profiles are set automatically according to dc:type metadata. It is not necessary to explicitly specify it.


The Snowflower EPUB Validator strictly checks EPUB specifications. Therefore, a major EPUB leader may also detect potential problems with compatibility that will not cause problems.

Download on the Mac App Store