For those who used KindleGen for personal library management rather than professional publishing, remains the best open-source alternative. It can convert almost any file format to AZW3 or KPF, offering even more customization than the original Amazon tools provided.
The simplest news for authors is that You no longer need a standalone tool to convert your book into a Kindle format before uploading. As long as your EPUB is validated and well-formatted, the KDP dashboard will handle the conversion for you during the publishing process. The Calibre Alternative kindlegen is no longer available for download
If you want a more "hands-on" design experience without needing to know HTML or CSS, is Amazon’s flagship formatting tool. It allows you to add professional themes, drop caps, and image layouts directly within the app. 3. Direct EPUB Uploads For those who used KindleGen for personal library