Free private EPUB checker

Validate an EPUB in your browser

Choose a DRM-free EPUB to verify its archive, required metadata, packaged resources, reading order and XML. The file never leaves your device.

EPUB preflight workflow inspecting package structure, images and page files before producing a verified book. — This focused preflight catches common structural failures. It does not replace the complete W3C EPUBCheck ruleset.

Local file check

Choose one EPUB

Nothing is uploaded. Use a file you own or have permission to inspect, up to 100 MB.

What this EPUB checker verifies

A fast structural preflight

Container

Confirms the ZIP directory, uncompressed mimetype entry, container.xml and package-document path.

Package graph

Checks required metadata, manifest resources and spine references against the files inside the EPUB.

Readable XML

Parses the package and XML-based manifest resources so malformed markup is not mistaken for a reader problem.

Need complete standards validation?

For publication, run the current official EPUBCheck release too. Use this browser validator for private first-pass triage, then use the error explainer to understand a reported code.

Open official EPUBCheck Explain an error code