Kindle File Format is a proprietary e-book file format created by Amazon.com with the extension
.azw that can be downloaded and read on devices like smartphones, tablets, computers, or e-readers that have Amazon's Kindle app.
|Kindle File Format|
|Internet media type|
(11 August 2015)
|Type of format||e-book file format|
|Extended from||HTML5, CSS3, MOBI|
Kindle devices and apps are designed to use Amazon's e-book formats: AZW that is based on Mobipocket; in fourth generation and later Kindles, AZW3, also called KF8; and in seventh generation and later Kindles, KFX. Kindles do not support the EPUB file format used by many other e-book readers. Similar to EPUB, Amazon's file formats are intended for reflowable, richly formatted e-book content and support DRM restrictions, but unlike EPUB, they are proprietary formats. AZW files debuted with the first Amazon Kindle in 2007.
Software such as the free and open source Calibre, Amazon's KindleGen, and the email based Send-to-Kindle service are available to convert e-books into supported Kindle file formats. Kindle devices can also display some generic document formats such as plain text (TXT) and Portable Document Format (PDF) files; however, reflowing is not supported for these file types.
In late 2011, the Kindle Fire introduced "Kindle Format 8" (KF8), also known as AZW3 file format. AZW3 supports a subset of HTML5 and CSS3 features, while acting as a container for a backwards-compatible MOBI content document.
In August 2015, all the Kindle e-readers released within the previous two years were updated with a new typesetting and layout engine that adds hyphens, kerning and ligatures to the text; e-books that support this engine require the use of the "Kindle Format 10" (KFX) file format. E-books that support the enhanced typesetting format are indicated in the e-book's description on its product page.
Calibre (stylised calibre) is a cross-platform open-source suite of e-book software. Calibre supports organizing existing e-books into virtual libraries, displaying, editing, creating and converting e-books, as well as syncing e-books with a variety of e-readers. Editing books is supported for EPUB and AZW3 formats. Books in other formats like MOBI must first be converted to those formats, if they are to be edited.Mobipocket
Mobipocket SA was a French company incorporated in March 2000 that created the .mobi e-book file format and produced the Mobipocket Reader software for mobile phones, personal digital assistants (PDA) and desktop operating systems.
The Mobipocket software package was free and consisted of various publishing and reading tools for PDAs, smartphones, mobile phones, the e-readers Kindle and iLiad, and applications on devices using Symbian, Windows, Palm OS, Java ME and Psion.
Amazon.com bought Mobipocket.com in 2005 and kept it running until October 2016, when it permanently shut down the Mobipocket website and servers.Rocket eBook
The Rocket eBook is an early commercial handheld e-reader that was produced by NuvoMedia in late 1998; it uses a LCD screen and can store up to ten e-books. E-books are loaded on the device by connecting it to a computer and the device has two page turn buttons. Rocket-compatible e-books were sold online at Barnes & Noble and Powell's Bookstore. It had a retail price of $499.
The Rocket eBook was manufactured by NuvoMedia until 2000, when it was purchased by Gemstar-TV Guide International for $187 million. After purchasing NuvoMedia and merging it with SoftBook, Gemstar released an e-reader called the RCA eBook Reader.