Guide
The self-publisher’s EPUB checklist
Store rejections cost you days each round trip, and their error messages are famously vague. Run this checklist before you submit and you'll catch nearly everything KDP, Apple Books and Kobo Writing Life actually bounce books for. Every check runs in your browser – your unpublished manuscript never touches a server.
1 · Start from clean source
If you write in Word, structure with real heading styles – every chapter starts with
Heading 1, not big bold text. Then convert with the
DOCX to EPUB converter, which maps headings to chapters and
strips the Word cruft that store converters choke on. Writing in plain text or Markdown?
TXT to EPUB does the same with # headings.
2 · Validate the structure
Drop the EPUB on the validator. You're looking for zero errors: well-formed content files (one unclosed tag fails a whole KDP upload), no missing files, no broken internal links, a proper navigation document. Fix what it finds – most issues link straight into the right tool – and re-validate until clean.
3 · Get the metadata store-perfect
Open the metadata editor and check, in order:
- Title – exactly as it should appear on the store listing, no "final_v3".
- Author – consistent with your other books, or series pages won't group.
- Language – a valid tag like
enoren-GB. Its absence is the most common silent rejection. - Series name and number – written in both conventions readers use, if the book belongs to one.
- Description – many readers display it; don't ship an empty one.
- ISBN – if you bought one; leave clean if not (KDP assigns an ASIN regardless).
4 · Cover, inside and out
Stores want the marketing cover uploaded separately, but the EPUB should still declare its own cover image – that's what shows in reader libraries. KDP's recommended cover is 2,560×1,600px; embed a reasonable version in the book (the metadata editor replaces covers) and keep the full-resolution original for the store upload.
5 · Watch the weight
KDP charges delivery costs against your royalty on the 70% plan – a bloated book is literally money lost per sale. Run the fixer even on a book that validates: it reports how much of your file is images and recompresses anything oversized with no visible quality loss on-device.
6 · Read it like a reader
Open the final EPUB in at least two real apps (Apple Books, Calibre's viewer, Kobo's app – any two). Check: the table of contents jumps correctly; chapter one starts where it should; images sit where you placed them; and the book responds to font-size changes without layout breaking. Five minutes here catches what automated checks can't – the "it's valid but looks wrong" class of problem.
❦
The thirty-second version
- Headings-structured source → convert
- Validate to zero errors
- Metadata: title, author, language, series, description
- Cover declared in-book; hi-res kept for the store
- Fixer pass for size (delivery costs!)
- Manual read-through in two apps
Do these six and the store's converter becomes the least of your launch worries.