What Is The Difference Between EPUB VS Mobi? The main difference between EPUB and MOBI is that EPUB is widely supported across all platforms whilst MOBI is predominantly a Kindle format. So what's stopping EPUB from being the single digital book format? What is a mobi file? Does Moby prefer mobis to EPUBs? One can only. mobi is Amazon's proprietary software for its ebooks. What is a MOBI file (Now AZW3)?. ePub files can be read natively by Apple devices, Windows 10 (Edge), Kobo, Sony Reader, Adobe Digital Editions, and more. EPUB vs MOBI? If you're wondering whether you should publish your ebook as an EPUB or MOBI file, read this article to decide which file type.