Mobipocket file format


Amazon Kindle



Mobipocket Application

Official Documentation

The Mobipocket file format is based on an old e-book standard, OEB (1999), which is pretty much plain HTML.

Mobipocket as a company extended this format a bit, through various tags such as the support for page break for example.

Although OEB and Mobipocket are both a bit old and limited (EPUB is the new standard for e-books), the format is still popular for various reasons, including Amazon's decision to use Mobipocket as the core format for the Kindle and the fact that Mobipocket Reader is available on a very large selection of devices.


Aside from the official Mobipocket Application, various other reading system can read Mobipocket files including Stanza Desktop and FBReader.


Feedbooks fully support the Mobipocket file format and can output any content available on the site in this format.

.prc or .mobi ?

Unlike the new e-book standard (EPUB), the previous standard did not specified a standard container for e-book files.

The .prc extension is inherited from the first releases of Mobipocket on Palm devices, where this extension is quite generic.

The .mobi extension on the other hand is specific to Mobipocket files.

Although .mobi is recommended (less confusing than .prc) some older versions of the Mobipocket Reader might only detect .prc files. You'll notice that on Feedbooks, Mobipocket books downloaded using the normal website have the .mobi extension, while the same books on the mobile website will have the .prc extension.