A KFX‑ZIP is essentially a collection of the KFX container’s internal files zipped together. Simply renaming or extracting won’t give you a valid EPUB.
The "story" of converting a file to EPUB is essentially a journey of bypassing Amazon's proprietary ecosystem to regain control over your purchased digital books. KFX-ZIP (often seen as a folder containing multiple .kfx components) is Amazon’s modern format designed for "Enhanced Typesetting," but it is notoriously difficult to open outside of official Kindle apps.
GitHub (search for "DeDRM_tools") What it is: A set of Python scripts that integrate into Calibre. When you import a .kfx-zip file, DeDRM detects the encryption, looks for a Kindle serial number (which you provide), and removes the DRM on-the-fly as the file enters Calibre.
Here is the most tested, community‑supported method as of 2025–2026:
To perform this conversion, you will need the following: