AZW4 is an ebook format developed by Amazon for Kindle devices. It is based on the EPUB standard but includes DRM protection for preventing unauthorized distribution. AZW4 files are typically used for selling ebooks on Amazon’s Kindle platform and are optimized for reading on Kindle devices and apps.
AZW3 is a proprietary ebook format developed by Amazon for Kindle devices. It supports more complex content than older formats like AZW, including HTML5 and CSS3 elements, embedded fonts, and multimedia. AZW3 files provide better compatibility and richer features for modern Kindle devices and apps.