A post that was relatively obscure last month Good e-reader Claims that Amazon will eventually allow the Kindle to read EPUB files The story was picked up by all the major tech sites, and for a while, there was a lot of fun After all, this is a feature that owners have been wanting since the first Kindle was released in 2007 But instead of supporting the open ebook format, Amazon has always insisted on bringing its own proprietary format for its readers to use. Accordingly, many users have reverted to third-party programs that can reliably convert their personal libraries to the Amazon format that best suits their particular Kindle.
Native support for EPUB will reduce the hassle for many people using Kindle, but alas, this is not supposed to happen. It didn’t take long before the original post was updated to make it clear that Amazon had just added support for their EPUB. Send to Kindle The service is still an improvement, as it offers relatively less effort to get open format files on your personal device; But when files are sent through the service, they will be converted to Amazon’s KF8 / AZW3 format, which may not always be what you expect. At the same time Send to Kindle The documentation states that support for AZW and MOBI files will be removed later this year, as older formats were not compatible with all the features of the latest Kindle models.
If you think it’s a lot of unnecessary confusion to get plain-text files to display in the world’s most popular erider, you’re not alone. If EPUB already has a recognized industry standard, users will not have to go through a double-file format alphabet soup. But when one of the readers of Amazon seems to be using it, it seems like a good time for a brief rounddown of various ebook formats and see how we got into this mess in the first place.
EPUB
With the release of version 1.0 of the Open Ebook Publication Structure (OEBPS), the history of the EPUB format can be traced back to 1999. Used by some of the first dedicated electronic readers of Sony and Intel’s choice, it consists largely of an exposed zip archive containing pages written in XHTML format, with CSS used for styling. OEBPS has gone through several revisions over the years and in 2007 it became the official technical standard of the International Digital Publishing Forum (IDPF). At that time it was named EPUB, short for electronic publication.
EPUB continues to evolve over the years, and in 2016 IDPF merged with the World Wide Web Consortium (W3C) to bring the publishing industry online with the latest in web development. The current version (3.2) of the EPUB format was released in May 2019, and it offers features like the ability of Internet-connected devices to load fonts and other content from outside the container file.
Although the 3.x branch has made some fairly large changes to the original format for better handling of multimedia content, EPUB can still be considered as a relatively easy web page to end up in a zip file. Because they are so easy to parse and render, you can find EPUB Reader applications even on very low-end devices.
It is also worth noting that EPUB formats Permission For digital rights management (DRM), this is not part of the standard. This means that if a vendor wants to apply DRM to EPUB, they have to figure out how to do it themselves. Theoretically this could lead to the problem of inconsistencies between vendor-specific solutions, but in reality, most people who use EPUB are doing so specifically because they are DRM-free.
MOBI / AZW
Even older than EPUB, MOBI has its origins in the PalmDOC format since 1996. Originally conceived as a way to save large text files in Palm Pilot, the format offers very little in the way of formatting beyond the ability to identify start and end points. The paragraph though provides basic bookmarking capabilities, which in some cases were used to offer a preliminary table of contents. Since the PalmDOC standard was a variation of the “Palm Database” file, it also had the ability to store several bits of metadata in a standard title, such as author’s name, book title, and current reading location.
While suitable for early low-resolution display by early Palm pilots, the lack of any real format support at PalmDOC became a liability due to hardware improvements. In 2000, developers of ebook reader applications on MobiPocket, Palm, Symbian and later BlackBerry devices decided to take matters into their own hands and expand PalmDOC. They added markdown language like HTML, improved support for images, and it was an open format, even borrowed from OEBPS. Since they didn’t have the ability to call it an update to the original PalmDOC, they dubbed the MOBI they created.
Amazon bought MobiPocket in 2005 and the story would have stopped here had it not been for the rights of MOBI. But instead of using the format for Kindle, they added a new DRM scheme and cranked the LZ77 compression of the format to the maximum. Since the first-gen Kindle only offered a relatively negligible 250 MB of onboard storage and was limited to downloading new titles over 3G cellular connections, they wanted to shave as much as possible.
This tweaked version of MOBI, which has become the standard format for Amazon’s ebook empire, was dubbed AZW. From here Amazon basically started using AZW as a blanket word for their ebook containers and the actual formats below started to get a bit blurry. In the early days, it was possible to come across other similar named file types:
AZW1
Officially known as Topaz, this proprietary Amazon format has little to do with MOBI / AZW outside of a shared DRM scheme and similar metadata headers. In addition to supporting larger images than previous formats, it was unique in that each title could include its own fonts and glyphs without relying on the Kindle itself. This makes it suitable for old book or non-English work, as it can better retain the original text and style.
AZW2
It’s not really an ebook format at all, so don’t be surprised if you have never seen one. Rather, it is a container file for executable Kindle applications and games.
KF8 / AZW3
With the release of the first Kindle Fire tablet in 2011, Amazon needed a new layout that could handle multimedia content. The answer was KF8, which is basically a combination of EPUB and MOBI. In fact, it specifically supports some EPUB 3.x features such as HTML5 and CSS3. New support for both fixed-layout pages and SVG images makes this format suitable for comic books, which was a big selling point for the Kindle Fire’s large color display.
Instead of maintaining two different file formats, Amazon has decided to move all its readers to AZW3 and create new values for the marketplace. While electronic paper Kindles may not necessarily benefit from the features offered by the new format, everyone outside of the first and second generation is able to read them, thanks to the unnecessary MOBI header information that is specifically reserved for backwards compatibility.
KFX / AZW8
With the release of Kindle Paperwhite 3 in 2015, Amazon has launched their latest format, KFX. Technical information about KFX is a bit difficult to find, as Amazon seems to have built it internally as their “final” book format. Some new improvements include an advanced typesetting engine, additional fonts and support for JPEG XR images. It rolls in support of video and interactivity, theoretically allowing the same format to be used for both books and software applications.
But perhaps the most obvious change was the improved DRM, which has caused a lot of headaches for users who want to read ebooks purchased by Amazon on other devices. At the moment the format and DRM are well understood that it can be handled by third party software, but it takes additional steps and intermediary tools that are not required for AZW3 content.
It is generally recommended that anyone who wants to maintain their own local library of ebook files should avoid this format altogether – although most of Amazon’s libraries have changed, this may mean you have to buy your books elsewhere.
Alexandria on your hard drive
If you ever read books bought from Amazon on your Kindle, you probably don’t have to worry about it. To their credit, Amazon has largely perfected the e-book shopping and dining experience – after all, the Kindle has become the Defecto Reader. All of these technological changes are hidden from view, and for the most part, tap into the book you want to read and take your life.
But for those of us who want to dedicate their books from multiple marketplaces, keep an offline copy of the books they bought, or read their Amazon books on non-Amazon readers, things can get a little messy. The best advice I can give you, if you are able to get so far without hearing it already, is to pick up a remarkable copy of Kovid Gayal. Caliber.
This cross-platform GPLv3 program allows you to create a format-agnostic virtual library that resides on your local computer and performs seamless device-specific file conversions while uploading to your readers. It may not be as easy as spending your days in the walled garden of Amazon, but for users who claim a little more control over their digital content, there is a price to pay.