Check if an EPUB is valid
Runs W3C EPUBCheck + accessibility audit + structural checks. Drag an EPUB below.
Drop an .epub file here
or click to pick
Skip the Java epubcheck step (useful if Java isn't installed)
Detect front / main / back matter
Opens your EPUB and classifies every chapter as frontmatter, bodymatter, or backmatter — so you see the book the way Kindle does.
Drop an .epub file here
or click to pick
Build ONIX 3.0 for a retailer
Fill in the basics, pick a retailer profile. You'll get the XML + a validation report (XSD + codelists + retailer rules).
Convert a document
DOCX / RTF / ODT / TXT → EPUB, or EPUB → PDF / DOCX / MOBI. Some targets need extra tools installed — we'll tell you if so.
Drop your source file here
.docx, .doc, .rtf, .odt, .txt, or .epub
For .docx → .epub: preserves Word paragraph styles (Heading 1 as chapter break, block quotes, drop caps, dedication/epigraph, images). Uncheck to use the simpler pandoc path.
Build an EPUB from chapters
Paste your chapters below as plain text or simple HTML. Each one becomes its own chapter file with proper prelim / main / back classification.