Kindle File Format

Last updated
Kindle File Format
Amazon logo.svg
Filename extension
.azw, .azw3, .kfx
Internet media type
application/vnd.amazon.mobi8-ebook
Developed by Amazon.com
Initial release2007
Latest release
10
11 August 2015
Type of format e-book file format
Extended from HTML5, CSS3, MOBI
Open format?No

Kindle File Format is a proprietary e-book file format created by Amazon.com that can be downloaded and read on devices like smartphones, tablets, computers, or e-readers that have Amazon's Kindle app. E-book files in the Kindle File Format originally had the filename extension .azw; version 8 (KF8) introduced HTML5 & CSS3 features and have the .azw3 extension, and version 10 introduced a new typesetting and layout engine featuring hyphens, kerning, & ligatures and have the .kfx extension.

History

Kindle devices and apps are designed to use Amazon's e-book formats: Image Compress AZW that is based on Mobipocket; in fourth generation and later Kindles, AZW3, also called KF8; and in seventh generation and later Kindles, KFX. [1] When uploaded via the Send to Kindle service Kindles now 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, [2] [3] 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. [4] AZW3 supports a subset of HTML5 and CSS3 features, [5] while acting as a container for a backwards-compatible MOBI content document. [6] [7]

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. [8] E-books that support the enhanced typesetting format are indicated in the e-book's description on its product page.

In 2017, Amazon released Kindle Create, a tool that can convert Microsoft Word files to Kindle file format. [9]

In 2022, while the Send-to-Kindle service only supported the original .mobi/.azw ebook formats (along with some other non-ebook file formats), [10] Amazon announced removing this support in favor of .epub which will be converted to Amazon's KF8 (.azw3) from late-2022. [11] [12] [10]

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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.

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<span class="mw-page-title-main">EPUB</span> E-book format

EPUB is an e-book file format that uses the ".epub" file extension. The term is short for electronic publication and is sometimes stylized as ePub. EPUB is supported by many e-readers, and compatible software is available for most smartphones, tablets, and computers. EPUB is a technical standard published by the International Digital Publishing Forum (IDPF). It became an official standard of the IDPF in September 2007, superseding the older Open eBook (OEB) standard.

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ebook Book-length publication in digital form

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<span class="mw-page-title-main">Kobo eReader</span> Family of e-book readers

The Kobo eReader is an e-reader produced by Toronto-based Kobo Inc. The company's name is an anagram of "book". The original version was released in May 2010 and was marketed as a minimalist alternative to the more expensive e-book readers available at the time. Like most e-readers, the Kobo uses an electronic ink screen. The Arc tablet series, released between 2011 and 2013, was based on LCD technology instead.

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<span class="mw-page-title-main">Reflowable document</span> Electronic document with fluid layout

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<span class="mw-page-title-main">Amazon Fire</span> Amazon Fire tablet timeline

The Amazon Fire, formerly called the Kindle Fire, is a line of tablet computers developed by Amazon. Built with Quanta Computer, the Kindle Fire was first released in November 2011, featuring a color 7-inch multi-touch display with IPS technology and running on Fire OS, an Android-based operating system. The Kindle Fire HD followed in September 2012, and the Kindle Fire HDX in September 2013. In September 2014, when the fourth generation was introduced, the name "Kindle" was dropped. In later generations, the Fire tablet is also able to convert into a Smart speaker turning on the "Show Mode" options, which the primary interaction will be by voice command through Alexa.

<span class="mw-page-title-main">Google Play Books</span> Digital distribution service for ebooks

Google Play Books, formerly Google eBooks, is an ebook digital distribution service operated by Google, part of its Google Play product line. Users can purchase and download ebooks and audiobooks from Google Play, which offers over five million titles, with Google claiming it to be the "largest ebooks collection in the world". Books can be read on a dedicated Books section on the Google Play website, through the use of a mobile app available for Android and iOS, through the use of select e-readers that offer support for Adobe Digital Editions, through a web browser and reading via Google Home. Users may also upload up to 2,000 ebooks in the PDF or EPUB file formats. Google Play Books is available in 75 countries.

<span class="mw-page-title-main">Kindle Store</span> Online e-book e-commerce store operated by Amazon

The Kindle Store is an online e-book e-commerce store operated by Amazon as part of its retail website and can be accessed from any Amazon Kindle, Fire tablet, or Kindle mobile app. At the launch of the Kindle in November 2007, the store had more than 88,000 digital titles available in the U.S. store. This number increased to more than 275,000 by late 2008 and exceeded 765,000 by August 2011. In July 2014, there were over 2.7 million titles available. As of March 2018, there are over six million titles available in the U.S. Content from the store is purchased online and downloaded using either Wi-Fi or Amazon's Whispernet to bring the content to the user's device. One of the innovations Amazon brought to the store was one-click purchasing which allowed users to quickly purchase an e-book. The Kindle Store uses a recommendation engine that looks at purchase history, browsing history, and reading activity, and then suggests material it thinks the user will like.

<span class="mw-page-title-main">Foliate (software)</span> E-book reading application for Linux

Foliate is a free e-book reading application for desktop Linux systems. The name refers to leaves, meaning "(getting) leafy" or "…-leaved".

References

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  2. "Kindle Publishing Programs". Amazon.com. July 12, 2011. Archived from the original on August 15, 2011. Retrieved August 15, 2011. Now via Internet Archive.
  3. "KindleGen". Amazon.com. Archived from the original on September 5, 2019. Retrieved February 7, 2019.
  4. Kindle Format 8 Archived 2017-03-29 at the Wayback Machine , Amazon.com, October 2011.
  5. "List of supported HTML tags and CSS elements". Amazon. Archived from the original on 14 December 2019. Retrieved 4 August 2012.
  6. Sabrina Ricci (March 6, 2012). "The New Kindle Format (KF8)". Digital Pubbing. Archived from the original on April 23, 2019. Retrieved September 29, 2018.
  7. "Amazon Throws A Minor Curveball With HTML5-Powered Kindle Format 8" Archived 2017-08-15 at the Wayback Machine , TechCrunch, October 20, 2011.
  8. Kindle eBooks with Improved Typography Use New KFX File Format Archived 2019-04-18 at the Wayback Machine . Retrieved 11 August 2015
  9. "Kindle Create: A New Ebook Conversion Tool". EpubSecrets. April 6, 2017. Archived from the original on February 25, 2020. Retrieved February 25, 2020.
  10. 1 2 "Learn About Sending Documents to Your Kindle Library". Amazon. Archived from the original on January 25, 2022. Retrieved 2022-05-04.
  11. Michael Kozlowski (April 30, 2022). "The Amazon Kindle will support EPUB in late 2022". Good E-Reader. Archived from the original on May 4, 2022. Retrieved May 7, 2022.
  12. Michael Cavacini (2022-05-04). "Amazon Kindle Will Support EPUB Books, Abandoning MOBI Format". michaelcavacini.com. Archived from the original on 2022-05-04. Retrieved 2022-05-04.