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Chaekgalpi Tools › E-books
Upaper EPUB Checker
Checks an EPUB before you submit it to Upaper, a Korean self-publishing platform. Catches rejection causes in advance: cover, copyright page, table of contents, forbidden tags.
Windows program · MIT · v0.2.7 · Updated 2026-10-14
For Windows. The file is unsigned, so if "Windows protected your PC" appears the first time, choose "More info → Run anyway".
Chaekgalpi Tools are made by the person who runs Chaekgalpi Library, a Korean-language web service for keeping a reading log. About Chaekgalpi Library (Korean) →
How to use
- Download the zip, unpack it and run upaper-epub-check.exe (no Python needed).
- Drop an EPUB file and the results open as an HTML report.
- Fix every "Error" (a possible rejection cause); "Warnings" are recommended specifications.
What it checks
- EPUB 2 version and toc.ncx; the cover (first page, duplicates, size, RGB); the publisher name.
- The five items on the copyright page (title, author, publisher, publication date, price) and the ISBN check digit.
- Table-of-contents limits and broken links, forbidden tags (script, iframe and so on), hard-coded black text colour (a night-mode problem).
- Broken image and font references, metadata (dc:title and the rest).
Mainly for people publishing on Upaper, but most of the checks apply to any EPUB 2 submission.
Since v0.2.6, the program sends only its name and version to the Chaekgalpi server when it starts, to check whether a newer version exists. No file is sent, it asks once a day, and you can turn it off in the settings.
Other tools in this group
- TXT to EPUB — Turns a plain-text file into an EPUB e-book without garbled characters. Chapter headings are detected and a table of contents is built.
- Ebook Cover Maker — Type a title, author and publisher name and get an e-book cover that passes self-publishing platform checks, inserted straight into your EPUB. A compliance tool, not a design tool.
- EPUB Font Unlock — Removes the hard-coded fonts from an EPUB whose typeface will not change on your e-reader, so you can read it in the font you choose.