Mobipockets

Mobipockets, often styled as Mobipocket, was a software company based in Paris, France, that developed the Mobipocket eBook format and related reading software. The company's flagship formats and tools—MOBI (often stored in files with .mobi or .prc extensions) and the Mobipocket Reader—were designed for mobile and handheld devices and supported by multiple platforms, including Palm OS, Windows Mobile, and Symbian.

The MOBI format is a compact, proprietary ebook format derived from the Open eBook (OEB) standard, with HTML-like content, CSS for styling, embedded images, and a structure optimized for mobile devices. Mobipocket also offered a Creator tool used to convert from common formats into MOBI.

In 2005, Amazon acquired Mobipocket SA. The MOBI format became one of the primary ebook formats for Kindle devices and apps, and the Mobipocket reader technology influenced subsequent Amazon ebook software. After the acquisition, the Mobipocket brand gradually faded from the market as Amazon integrated the technology into Kindle ecosystems and migrated customers to new formats (AZW, AZW3, KFX).

Legacy: Mobipocket helped popularize portable, vendor-neutral ebook distribution and laid groundwork for DRM-enabled eBooks on mobile devices. While the original Mobipocket service and standalone apps are largely discontinued, MOBI remains a recognized format on older Kindle devices and in legacy libraries, and it is still readable by many e-readers that support the format, though newer Kindle formats have superseded it.