A format outlived by its own books
MOBI powered e-readers since the 2000s, and Kindle libraries grew huge in it. Then Amazon dropped MOBI support for sending documents, removed its old conversion tools, and the ecosystem moved to newer formats. The books did not go anywhere — they sit in folders and backups, increasingly hard to open.
This tool reads MOBI and its successor AZW3 directly in your browser — chapters, images, metadata, reading order — and repacks everything as a standard EPUB that opens in Apple Books, Google Play Books, Calibre, Kobo and every modern reading app. Book files are personal libraries; converting them should not require uploading them to anyone, and here it does not.
The honest limitation: DRM
Books bought from the Kindle store are usually DRM-protected, and no honest converter can open them — this tool will tell you so instead of producing garbage. DRM-free books convert cleanly: purchases from DRM-free stores, Project Gutenberg classics, self-published files and technical e-books.