Check your Ebooks quality with Helicon Books EPUB validator
EPUB validator make sure an EPUB file is written according to the standard and will thus be readable on any standard compliant reading system.
In reality not all reading systems are created equal and some of them does not fully conform to the standard, also some reading system interpret the standard differently, Helicon Books validator adds tests for known problems in reading systems.
Some stores also have specific requirements for EPUB files, for example apple iBook store requires a specific section in the table ofcontents that is not mandatory by the standard. Apple also requires an additional proprietary file to be present, Kobo has a similar requirement. Helicon Books validator will generate warnings on files that may not be suitable for uploading to Apple or Kobo, this may actually save you money since apple charges for each upload.
Helicon Books validator also checks CSS of EPUB files and will issue warnings on fonts not used by system or fonts that are used but not present in the file.
Helicon Validator is an easy to use web based service, simply upload your EPUB and get comprehensive results list.
Results are given in plain English instead of the cryptic and hard to grasp results from IDPF epubcheck. In addition, you can get more tips on most errors or warning such as why it happens etc.
Helicon Books validator uses the latest epubcheck from IDPF and in addition to conveying results in plain English it adds the following tests: