Free Tool

Free EPUB validator for authors and publishers.

Upload a DRM-free .epub file and we will run it through EPUBCheck so you can catch packaging and spec problems before retailers do. Your uploaded file is deleted immediately after the check finishes.

Simple check. Clean output. No clutter.

  • Runs against the industry-standard EPUBCheck validator
  • Works with normal DRM-free EPUB uploads
  • Checks metadata, links, package structure, navigation, and EPUBCheck compliance
  • Deletes temporary upload files right after validation
As soon as you pick a file, we validate it. No extra upload button nonsense.
EPUB validation guide

What this EPUB validator checks before you publish.

Retailers can reject an ebook for small packaging, metadata, navigation, or manifest issues. A quick validation pass gives you a clearer repair list before you upload the file to KDP, Apple Books, Kobo, Ingram, or another publishing channel.

EPUB package structure

EPUBCheck reviews the container, OPF package file, manifest, spine, MIME type, and other required pieces that tell reading systems how the ebook is assembled.

Navigation and links

The validator flags missing resources, broken references, navigation-file problems, duplicate IDs, malformed XHTML, and other issues that can create reader-display problems.

Metadata and compatibility

Validation helps catch standards problems before publication so you can fix the file once instead of chasing retailer rejections or support messages after launch.

Why validate?

Avoid preventable EPUB upload problems.

Even a good-looking ebook can fail validation if the internal package is missing a resource, the table of contents is malformed, or an image path does not match the manifest. Running an EPUB validator before publishing is a simple quality-control step for any author preparing an ebook release.

If the report shows errors, fix the source file or conversion workflow first. Then re-run the validator until the EPUBCheck output is clean enough for the channels you plan to use.

How to use the validator

  1. Choose a DRM-free .epub file from your computer.
  2. Wait while the file runs through EPUBCheck.
  3. Review any warnings or errors in the output.
  4. Fix the EPUB, then validate the revised file before uploading to retailers.

Need a repair path? Start with our self-publishing checklist, review the Amazon Kindle Direct Publishing guide, or use EbookConvert.pro for a clean Word-to-EPUB conversion.