What KDP is, and why Amazon wants one particular file

KDP (Amazon's free self-publishing platform) is a website where you upload a file of your book, and Amazon turns it into something people can buy. There is no publisher, no contract and nothing to pay in advance. Amazon simply takes a share of every copy sold.

The name stands for Kindle Direct Publishing, which is misleading: the system does not only sell to Kindle. It also prints real books on paper and ships them to the buyer.

What actually happens there

You open an account, fill in a few fields — book title, author name, a short description, language — and upload two files: one with the content of the book and one with the cover.

From that moment Amazon does two things. The digital edition it converts into a format a Kindle can display. The printed edition it does not print at all, until somebody orders a copy — and then it prints that copy at a press near the buyer's address and ships it.

This is the part that is hardest to believe at first. There are no boxes, no warehouse, and no risk of hundreds of unsold copies sitting in your living room. A book that does not sell was simply never printed.

Why Amazon insists on a particular file

Because your book has to look right on a small phone screen, on a dedicated reading device, and on a tablet — and on each of them the reader can make the letters bigger.

That is only possible if the text "flows", meaning it has no fixed pages decided in advance. So Amazon prefers files where the text is text, rather than a picture of text.

The list of files Amazon accepts for a digital book includes an ordinary Word file, EPUB (the standard format for digital books), plain text and also PDF — though the last one is supported in a limited set of languages only, because it is built around a fixed page.

The practical conclusion is simple. If the book was written in Word, you already have the right file. If all you have is a PDF the designer sent you, there is an extra step ahead.

Where translation comes into this

Here is the point that surprises almost every author: a translated book is not a "version" of the existing one. It is a separate book in the system.

It has its own page on the site, its own cover, its own description and its own price. The reviews you collected in the original language do not move across, and neither does the ranking. It starts from zero.

That sounds frustrating, but there is logic in it. A reader looking for a book in Spanish gets a Spanish result with a description they can read. One listing mixing two languages would confuse everybody.

In practice this means that when you translate a book, you also need a translated description and a title that works in the new language. We wrote about that separately in titles and back-cover text get rewritten, not translated.

What to do before you upload

The main thing is to make sure the file itself is clean. Chapter titles marked as heading lines rather than bold text at size 18, no manual blank lines pushing a chapter onto a new page, and no pictures of text.

If you are planning a translation, this is also the right moment to tidy the file up, because every mess in the original travels into the translation. We covered that in how to prepare a book file before translation.

One last thing: the book's language is a field you choose at upload. It is easy to miss, and it is what decides whether a reader in France sees your book at all. Thirty seconds of attention there saves months of wondering why nobody finds it.

So where do you start

Open an account, upload the book in its original language, and see how it works. The system lets you correct and re-upload as often as you like, so a first upload is not a final decision.

Only once the first book is live does the question of another language become concrete. If you are already there, our frequently asked questions answer most of what comes up at that stage.