EPUB Validator

Check DRM-free EPUB 2 and EPUB 3 files with EPUBCheck and download a detailed conformance report.

Upload an EPUB to validate

DRM-free EPUB 2 and EPUB 3 files are supported up to 1 GB. Validation is read-only.

Conservative repairs only

Repair can correct mimetype placement and storage, remove leading ZIP junk, normalize uniquely resolvable internal path casing, rebuild container.xml when exactly one OPF exists, and safely repackage the EPUB.

Content stays unchanged

Convertr never invents content, rewrites prose or CSS, removes DRM, fetches remote resources, or hides unresolved errors. The repair report includes a change manifest and entry hashes.

EPUB Validator

Run EPUBCheck against a DRM-free EPUB and expose machine-readable and text validation reports.

Input
One DRM-free EPUB 2 or EPUB 3 file.
Output
EPUBCheck findings as JSON or text.
Real limitations
A clean report means the checked rules passed; it does not guarantee accessibility, visual quality, retailer approval, or device compatibility.
Privacy and data handling
one DRM-free EPUB 2 or EPUB 3 file is uploaded to a compatible Convertr worker only after you start the operation. Processing is automated, and temporary source and result files are deleted automatically after processing rather than retained as permanent storage.

How to use this tool

  1. Choose one DRM-free EPUB 2 or EPUB 3 file and wait for the page to validate it.
  2. Set the available output or inspection options, then start processing.
  3. Review the reported result and download EPUBCheck findings as JSON or text before the temporary link expires.

Common failure modes

Encrypted content, an invalid ZIP container, unsafe entries, or an unreadable package document stops validation.

Useful example

Validate novel.epub and download a text report that identifies a broken spine reference by file and line.