A User's Guide to Writing an EPUB Mimetype File

Definition of MIME type for EPUB documents

Digital books
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EPUB is fast becoming the digital platform to learn for e-book publishing. EPUB stands for Electronic Publishing and is the XML format from the International Digital Publishing Forum. By design, EPUB works with two languages, XHTML, and XML. This means once you have an understanding of the syntax and structure of these formats, creating an EPUB digital book will be a natural step up in the learning process. EPUB comes in three separate sections or folders.

  • Mimetype

In order to create a viable EPUB document, you must have all three.

Writing the Mimetype File

Of these divisions, mimetype is the most simplistic. Mimetype is an ASCII text file. A mimetype file tells the operating system of the reader how the ebook is formatted — the MIME type. All mimetype files say the same thing. To write your first mimetype document all you need is a text editor, such as Notepad. Type in this code on to the editor screen:


Save the file as "mimetype." The file must have this title in order to work correctly. Your mimetype document should only contain this code. There should be no additional characters, lines or carriage returns. Put the file into the root directory of the EPUB project. This means mimetype goes in the first folder. It is not contained in its own section.

This is the first step to creating your EPUB document and the easiest. All mimetype files are the same. If you can remember this tiny snippet of code, you can write a mimetype file for EPUB.