Validate EPUB ebooks online

Check an EPUB file for standards compliance, errors, and warnings before publishing.

You’ll need
EPUB80 MB max
You’ll get
Details
How long
Under 20s

Ensure your ebook is ready for distribution on Apple Books, Amazon Kindle, Kobo, and Google Play. This tool validates an EPUB ebook against official W3C EPUB standards and outputs a structured validation report.

How to validate an EPUB

  1. Upload an EPUB ebook file (.epub) up to 80 MB.
  2. Press Convert file.
  3. Download or inspect the structured JSON report detailing validation results and metadata.

What you get

A JSON validation report containing:

  • Validation summary and overall status (valid or invalid)
  • Itemized lists of errors, warnings, and formatting issues with line and column numbers
  • EPUB version and metadata checks (title, author, identifier, language)
  • Manifest item details and spine structure validation

When this helps

  • Before submitting an ebook to self-publishing platforms or retail stores
  • When debugging rendering or formatting issues in e-reader apps
  • To verify automated ebook generation pipelines without local software installation

Common questions