Technical Guide
Why Your EPUB Passes Amazon But Apple Rejects It (The Validation Gap)
Your EPUB passes Amazon KDP but gets rejected by Apple Books and Kobo. Here's why—and how to build books that pass all platforms.
2026-02-28 10 min read
Practical guides for indie authors on EPUB formatting, KDP validation, manuscript conversion, and getting your book retailer-ready without wasting hours on software.
Most formatting problems come down to the same handful of issues: manuscripts written in Google Docs with invisible styling, Word files polluted by years of copy-paste, automated converters that mangle italics and scene breaks, or EPUBs that pass Calibre but fail KDP validation.
The guides here cover those problems directly — what causes them, how to fix them yourself, and when it makes more sense to hand the file to a professional. Whether you're preparing your first manuscript or troubleshooting a KDP rejection on your fifth book, start with the article that matches your current problem.
Your EPUB got rejected with an error code you don't understand. Here's what RSC-012, RSC-005, OPF-014, and other common errors actually mean.
Your EPUB passes Amazon KDP but gets rejected by Apple Books and Kobo. Here's why—and how to build books that pass all platforms.
You got rejected with 'RSC-012: Fragment identifier is not defined.' Here's what it means, why it happens, and how to fix it.
Use this practical checklist to compare formatters, avoid vague quotes, and choose the right service before payment.
A practical pricing breakdown for indie authors: what affects ebook formatting cost, what should be included, and how to avoid overpaying.
Use this step-by-step checklist to prepare your manuscript, reduce revision cycles, and speed up EPUB delivery.
Not sure what goes before Chapter 1 or after The End? This guide shows what to include and what to skip.
Your EPUB passes Amazon KDP but gets rejected by Kobo and Apple Books. Here's why the validation gap exists and how I build books that pass all platforms.
Automated PDF to EPUB converters mangle formatting. Learn why Calibre and Zamzar fail—and why hiring someone is faster than fixing the mess.
Your Word doc has weird formatting, lost indents, and broken styles. Here's when DIY formatting will fail and why hiring a professional saves time and money.
Vellum limitations (Mac-only, no footnotes until v3.7) and Atticus bugs (sync issues, broken links) make professionals a better choice for complex books.
Amazon's validation catches broken links, invalid HTML, and accessibility issues. Learn what gets flagged and how to avoid rejection.
Google Docs invisible formatting breaks EPUB conversion. Learn why indents disappear and italics vanish—and why building from scratch is easier than fixing it.
Let me handle your EPUB formatting while you focus on writing. Professional results, 3-5 day turnaround, starting at $49.