Checking starts automatically once you pick a file
Browser-based
Your file is processed locally without waiting for a server conversion queue.
No upload required
Files stay in your browser, which is ideal for private drafts and personal libraries.
Free ebook tool
Merge and split ebook files without signup, credits, watermarks, or installation.
Why check an EPUB before publishing?
Most EPUB problems surface far from where they were created. A book that opens fine in one reader app may fail store ingestion or render blank chapters in another — packaging details like the mimetype entry or dead references are only noticed when something has already gone wrong.
A pre-publish check catches these issues while they are still cheap to fix. This tool inspects the package structure, required metadata, image accessibility and TOC quality, and tells you exactly which files are affected.
Errors, warnings and suggestions
Errors are problems that strict validators and store ingestion pipelines will flag — fix them before publishing. Warnings affect polish and accessibility: missing alt text, skipped heading levels or junk files. Suggestions are quality improvements, like adding a cover.
Every failed check links to a free tool on this site that fixes it, so you can go from report to repaired book without leaving your browser.
How to check an EPUB
Add your EPUB
Drop the file anywhere on the box. Checking starts automatically — nothing is uploaded.
Read the report
You get a verdict plus every failed check, grouped by severity, with the affected files listed.
Fix and re-check
Follow the links to the matching repair tools, then run the check again to confirm a clean report.
FAQ
No. EPUBCheck is the official standards validator; this tool runs a practical pre-publish check covering packaging structure, metadata, images, headings and TOC quality — the issues that actually break reading. For structural problems it finds, use the EPUB repair tool.
Book checked — ready to translate it?
Turn a foreign-language EPUB into a bilingual or fully translated book, chapter by chapter, right in your browser.
Translate this EPUB