Although ePub appears to be a more widely used eBook format than Mobi around the Web, the Kindles can't read it natively since it's tightly tied to Amazon's ecosystem. The difference between ePub and Mobi is that ePub is a free and open standard eBook file format that can be downloaded and read on more devices like smartphones, tablets, computers, or e-readers, while the Mobi is a specific eBook format specially developed for Amazon Kindle devices. EPUB and MOBI are two most well-known eBook formats for popular eBook readers in the market.
