Kepubify is fast, supports batch-processing, and converts most books in a fraction of a second—around 40-80x faster than Calibre.

Kepubify can handle malformed books, and often produces better output for them than other software.

Kepubify will handle complex books correctly, and will always output valid documents compatible with XHTML and HTML.

The conversion functions are tested against actual KEPUBs. And, where there are incompatibilities between EPUBs and KEPUBs, kepubify will attempt to fix them automatically.

Other software isn't required to run kepubify.

Options include converting new books only, punctuation smartening, find/replace, custom CSS, and controlling hyphenation.

Kepubify can be used at the same time or other e-book management tools, and it can even be used to pre-convert a Calibre library.

The book layout isn't modified unnecessarily, and extraneous features unrelated to conversion aren't included.

Kepubify is safe to run on untrusted books—it's secure against vulnerabilities like Zip Slip.

The seriesmeta tool allows series metadata for sideloaded books to be displayed, and covergen can pre-generate cover thumbnails for faster library browsing.

Page turns, font changes, highlighting, and searching are much more responsive on KEPUBs.

Fixed-layout, page spreads, MathML, HTML5, and other EPUB 3 features are only supported on the KEPUB reader.

Kobo EPUBs enable statistics including a chapter graph and estimated read time.

The Page Flip feature, which allows you to quickly skim pages by pressing the corner of the screen, is only available on KEPUBs.

On Kobo EPUBs, footnotes will appear as a pop-up dialog when supported by the original book.

Tap an image to zoom and pan it in a pop-up window.

Kobo displays cover images for KEPUBs correctly, unlike normal EPUBs which often end up with an ugly white margin.