by Guest Contributor
Dave Chesson

(Please note that Authorlink does not accept so-called
ad-embedded "guest posts." Our articles are juried)

Not long ago, the MOBI file for both reflowable and fixed submission to Amazon was the ebook
file that you had to upload to Amazon KDP (Kindle Direct Publishing).

However, starting in 2020, Amazon began phasing out this file type, in favor of the more popular

But why? Why would Amazon destroy the mobi file and what do they hope to gain. Also, what
does this mean for authors? These are the questions I hope to tackle in this article. But before
we get into that, let’s first take a look at exactly what a Mobi and EPUB file is.

What Is a MOBI File?

The MOBI file is a digital file for ebooks that was developed by Amazon, specifically for use on
their Amazon Kindle E readers, fire tablets, and mobile apps.

In essence, if you have ever read a book on a Kindle app or Kindle device, you were reading a
MOBI file. Authors had to have a MOBI file if they wanted to self-publish their book to KDP.
Additionally, if you wanted to side-load a free ebook (such as a reader magnet or an ARC copy),
that file also needed to be MOBI before you could do so.

But Amazon was alone in this endeavour because just about every other book marketing or
reader doesn’t work with Mobi or accept them. Which leads us to EPUB.

What Is an EPUB File?

An EPUB file is a more common form of digital ebook file. It has been around for longer, and it is
by far the most popular format outside of Amazon.
Indeed, the EPUB file is used in virtually every other ebook distributor, including Apple, Barnes
& Noble, Kobo, and more.

This meant that if you wanted to upload your book to Amazon and other ebook-distributing
platforms, you had to create two ebook files: one MOBI and one EPUB.
If you were using your own ISBN numbers, you had to have two of those as well, one for each
file type.

Learn more about the differences between different file types here.

What Happened to the MOBI File?

Now that we have a basic understanding of the difference between a MOBI and EPUB file, let’s
discuss what has happened between 2020 and 2022.

1. November 2020: Amazon recommends EPUB Instead of MOBI

This was the first sign that Amazon was phasing out the MOBI file. Beginning in late 2020,
Amazon began recommending that authors use EPUB files for uploading new books to Amazon
KDP, as well as updating old books.

This was significant, as Amazon had previously never allowed the EPUB to be used on that
platform. However, the MOBI file was still around, and you could still upload MOBI files to KDP.

2. June 2021: MOBI Reflowable Files Are No Longer Allowed on Amazon

Midway through 2021, Amazon took the next step. In June they announced that MOBI
reflowable files would no longer be permitted when uploading ebooks to KDP. Instead, they
continued to recommend the EPUB file.

3. April 2022: Shifting To EPUB for Kindle submission

In 2022, it was announced that, by the end of the year, Amazon would soon be removing the
ability to send MOBI files (both fixed and reflowable) to a Kindle and that it would be a stepped
phased approach.

Amazon KDPSimultaneously, Amazon announced support for the EPUB file when sideloading books onto your Kindle. Currently, you now have the ability to “Send to Kindle” an EPUB file, and later in the
year, you’ll have the ability to either use their software or do directly load an EPUB to a Kindle.

So, by end of 2022, you will no longer be able to.

So, What About MOBI Fixed Layout Files?

The last bastion of the MOBI file is fixed format. Amazon currently allows users to submit a
MOBI fixed file format when you submit your book to KDP for publishing.
However, talking with the Kindle software team, this too will one day be removed and authors
will no longer be able to work with MOBI in any capacity. At the time of this writing, no specific
date has been given yet.

What This Change Means for Authors

There are a number of ramifications from this change as Amazon moves away from MOBI to the
EPUB that authors should know and think about. Let’s take a look at some of them:

1. You Now Only Need One File To Publish Everywhere

Traditionally, if you wanted to publish in marketplaces outside of Amazon, you would need to
prepare two files: one MOBI and one EPUB.

Now that Amazon has embraced the EPUB, you only need to use one file for every store.
Additionally, you only need one ISBN, since there is only one file now.

2. Reader Magnets and ARC Editions No Longer Need a MOBI File

If you produced a free reader magnet to get people onto your newsletter, provided advanced
reader copies (ARC) to your readers to get reviews or used a free ebook of any kind, you are in

Previously, you had to use a MOBI file to deliver these free books, because Amazon had not yet
supported EPUB files for sideloading books.

That is no longer the case. Now you can send EPUB books to your Kindle without a problem,
saving you the extra step of converting your file to a MOBI file. If you’d like to learn more about
how to transfer an EPUB file to a Kindle, you can check out this resource.

3. Formatting for the Future

Formatting a book on your own without special software is extremely difficult. Although we now
only have to focus on one file format, the EPUB, making sure your formatter knows this is
incredibly important.

That’s why working with profesional formatters that understand the rules, like Authorlink®

formatting services is key. They know the requirements and have incredible experience with
EPUB files that will be accepted by all book markets without any problems.

In short, using a skilled team that has experience with this file format will save you time and
reduce headaches, which in turn gives you more time to focus on polishing your manuscript.

Final Thoughts: MOBI Is On the Way Out

I’m glad to say that Amazon is finally making the right moves and moving away from MOBI.
However, it is important for authors and their formatters to understand this very important move.
Luckily, Authorlink® formatting can do exactly that and take care of your formatting needs
without the hassle.

About the Author:

Dave Chesson is the creator of, a website devoted to teaching advanced
book Marketing which even Amazon KDP acknowledges as one of the best by telling users to
“Gain insight from Kindlepreneur on how you can optimize marketing for your books.” Having
worked with such authors as Orson Scott Card, Ted Dekker and more, his tactics help both Fiction and Nonfiction authors of all levels get their books discovered by the right readers. He’s also the founder of Publisher Rocket, a book marketing software, and, a book writing and formatting software.