Last updated
Electronic Publication (EPUB)
EPUB logo.svg
Filename extension .epub
Internet media type application/epub+zip
Magic number PK\x03\x04 (Zip)
Developed byInternational Digital Publishing Forum (IDPF)
Initial releaseSeptember 2007;12 years ago (2007 -09)
Latest release
(May 15, 2019;12 months ago (2019-05-15) [1] )
Type of format e-book file format
Contained by OEBPS Container Format (OCF; Zip)
Extended from Open eBook, XHTML, CSS, DTBook
Standard ISO/IEC TS 30135
Open format?Yes
Website www.idpf.org/epub

EPUB is an e-book file format that uses the ".epub" file extension. The term is short for electronic publication and is sometimes styled 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 standard. [2]


The Book Industry Study Group endorses EPUB 3 as the format of choice for packaging content and has stated that the global book publishing industry should rally around a single standard. [3] The EPUB format is implemented as an archive file consisting of XHTML files carrying the content, along with images and other supporting files. EPUB is the most widely supported vendor-independent XML-based (as opposed to PDF) e-book format; that is, it is supported by almost all hardware readers, except for Kindle. [4]


A successor to the Open eBook Publication Structure, EPUB 2.0 was approved in October 2007, [5] with a maintenance update (2.0.1) approved in September 2010. [6]

The EPUB 3.0 specification became effective in October 2011, superseded by a minor maintenance update (3.0.1) in June 2014. [7] New major features include support for precise layout or specialized formatting (Fixed Layout Documents), such as for comic books, [8] and MathML support. The current version of EPUB is 3.1, effective January 5, 2017. [9] The (text of) format specification underwent reorganization [10] and clean-up; format supports remotely-hosted resources and new font formats (WOFF 2.0 and SFNT) [11] and uses more pure HTML and CSS. [12]

In May 2016 IDPF Members approved World Wide Web Consortium (W3C) merger, [13] "to fully align the publishing industry and core Web technology". [14]

Version 2.0.1

EPUB 2.0 was approved in October 2007, with a maintenance update (2.0.1) intended to clarify and correct errata in the specifications being approved in September 2010. [6] EPUB version 2.0.1 consists of three specifications:

EPUB internally uses XHTML or DTBook (an XML standard provided by the DAISY Consortium) to represent the text and structure of the content document, and a subset of CSS to provide layout and formatting. XML is used to create the document manifest, table of contents, and EPUB metadata. Finally, the files are bundled in a zip file as a packaging format.

Open Publication Structure 2.0.1

An EPUB file uses XHTML 1.1 (or DTBook) to construct the content of a book as of version 2.0.1. This is different from previous versions (OEBPS 1.2 and earlier), which used a subset of XHTML. There are, however, a few restrictions on certain elements. The mimetype for XHTML documents in EPUB is application/xhtml+xml. [15] [lower-alpha 1]

Styling and layout are performed using a subset of CSS 2.0, referred to as OPS Style Sheets. This specialized syntax requires that reading systems support only a portion of CSS properties and adds a few custom properties. Custom properties include oeb-page-head, oeb-page-foot, and oeb-column-number. Font-embedding can be accomplished using the @font-face property, as well as including the font file in the OPF's manifest (see below). The mimetype for CSS documents in EPUB is text/css. [15] [lower-alpha 2]

EPUB also requires that PNG, JPEG, GIF, and SVG images be supported using the mimetypes image/png, image/jpeg, image/gif, image/svg+xml. Other media types are allowed, but creators must include alternative renditions using supported types. [15] For a table of all required mimetypes, see Section 1.3.7 of the specification.

Unicode is required, and content producers must use either UTF-8 or UTF-16 encoding. [15] This is to support international and multilingual books. However, reading systems are not required to provide the fonts necessary to display every unicode character, though they are required to display at least a placeholder for characters that cannot be displayed fully. [15]

An example skeleton of an XHTML file for EPUB looks like this:

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"><htmlxmlns="http://www.w3.org/1999/xhtml"xml:lang="en"><head><metahttp-equiv="Content-Type"content="application/xhtml+xml; charset=utf-8"/><title>Pride and Prejudice</title><linkrel="stylesheet"href="css/main.css"type="text/css"/></head><body>     ...   </body></html>

Open Packaging Format 2.0.1

The OPF specification's purpose is to "...[define] the mechanism by which the various components of an OPS publication are tied together and provides additional structure and semantics to the electronic publication." [16] This is accomplished by two XML files with the extensions .opf and .ncx.

.opf file

The OPF file, traditionally named content.opf, houses the EPUB book's metadata, file manifest, and linear reading order. This file has a root element package and four child elements: metadata, manifest, spine, and guide. Furthermore, the package node must have the unique-identifier attribute. The .opf file's mimetype is application/oebps-package+xml. [16]

The metadata element contains all the metadata information for a particular EPUB file. Three metadata tags are required (though many more are available): title, language, and identifier. title contains the title of the book, language contains the language of the book's contents in RFC 3066 format or its successors, such as the newer RFC 4646 and identifier contains a unique identifier for the book, such as its ISBN or a URL. The identifier's id attribute should equal the unique-identifier attribute from the package element. [16] [lower-alpha 3]

The manifest element lists all the files contained in the package. Each file is represented by an item element, and has the attributes id, href, media-type. All XHTML (content documents), stylesheets, images or other media, embedded fonts, and the NCX file should be listed here. Only the .opf file itself, the container.xml, and the mimetype files should not be included. [16] Note that in the example below, an arbitrary media-type is given to the included font file, even though no mimetype exists for fonts.

The spine element lists all the XHTML content documents in their linear reading order. Also, any content document that can be reached through linking or the table of contents must be listed as well. The toc attribute of spine must contain the id of the NCX file listed in the manifest. Each itemref element's idref is set to the id of its respective content document. [16]

The guide element is an optional element for the purpose of identifying fundamental structural components of the book. Each reference element has the attributes type, title, href. Files referenced in href must be listed in the manifest, and are allowed to have an element identifier (e.g. #figures in the example). [16] [lower-alpha 4]

An example OPF file:

<?xml version="1.0"?><packageversion="2.0"xmlns="http://www.idpf.org/2007/opf"unique-identifier="BookId"><metadataxmlns:dc="http://purl.org/dc/elements/1.1/"xmlns:opf="http://www.idpf.org/2007/opf"><dc:title>Pride and Prejudice</dc:title><dc:language>en</dc:language><dc:identifierid="BookId"opf:scheme="ISBN">123456789X</dc:identifier><dc:creatoropf:file-as="Austen, Jane"opf:role="aut">Jane Austen</dc:creator></metadata><manifest><itemid="chapter1"href="chapter1.xhtml"media-type="application/xhtml+xml"/><itemid="appendix"href="appendix.xhtml"media-type="application/xhtml+xml"/><itemid="stylesheet"href="style.css"media-type="text/css"/><itemid="ch1-pic"href="ch1-pic.png"media-type="image/png"/><itemid="myfont"href="css/myfont.otf"media-type="application/x-font-opentype"/><itemid="ncx"href="toc.ncx"media-type="application/x-dtbncx+xml"/></manifest><spinetoc="ncx"><itemrefidref="chapter1"/><itemrefidref="appendix"/></spine><guide><referencetype="loi"title="List Of Illustrations"href="appendix.xhtml#figures"/></guide></package>
.ncx file

The NCX file (Navigation Control file for XML), traditionally named toc.ncx, contains the hierarchical table of contents for the EPUB file. The specification for NCX was developed for Digital Talking Book (DTB), is maintained by the DAISY Consortium, and is not a part of the EPUB specification. The NCX file has a mimetype of application/x-dtbncx+xml.

Of note here is that the values for the docTitle, docAuthor, and meta name="dtb:uid" elements should match their analogs in the OPF file. Also, the meta name="dtb:depth" element is set equal to the depth of the navMap element. navPoint elements can be nested to create a hierarchical table of contents. navLabel's content is the text that appears in the table of contents generated by reading systems that use the .ncx. navPoint's content element points to a content document listed in the manifest and can also include an element identifier (e.g. #section1). [16] [18]

A description of certain exceptions to the NCX specification as used in EPUB is in Section 2.4.1 of the specification. The complete specification for NCX can be found in Section 8 of the Specifications for the Digital Talking Book. [18]

An example .ncx file:

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE ncx PUBLIC "-//NISO//DTD ncx 2005-1//EN""http://www.daisy.org/z3986/2005/ncx-2005-1.dtd"><ncxversion="2005-1"xml:lang="en"xmlns="http://www.daisy.org/z3986/2005/ncx/"><head><!-- The following four metadata items are required for all NCX documents,including those that conform to the relaxed constraints of OPS 2.0 --><metaname="dtb:uid"content="123456789X"/><!-- same as in .opf --><metaname="dtb:depth"content="1"/><!-- 1 or higher --><metaname="dtb:totalPageCount"content="0"/><!-- must be 0 --><metaname="dtb:maxPageNumber"content="0"/><!-- must be 0 --></head><docTitle><text>Pride and Prejudice</text></docTitle><docAuthor><text>Austen, Jane</text></docAuthor><navMap><navPointclass="chapter"id="chapter1"playOrder="1"><navLabel><text>Chapter 1</text></navLabel><contentsrc="chapter1.xhtml"/></navPoint></navMap></ncx>

Open Container Format 2.0.1

An EPUB file is a group of files that conform to the OPS/OPF standards and are wrapped in a ZIP file. [19] The OCF specifies how to organize these files in the ZIP, and defines two additional files that must be included.

The mimetype file must be a text document in ASCII that contains the string application/epub+zip. It must also be uncompressed, unencrypted, and the first file in the ZIP archive. This file provides a more reliable way for applications to identify the mimetype of the file than just the .epub extension. [17]

Also, there must be a folder named META-INF, which contains the required file container.xml. This XML file points to the file defining the contents of the book. This is the OPF file, though additional alternative rootfile elements are allowed. [17]

Apart from mimetype and META-INF/container.xml, the other files (OPF, NCX, XHTML, CSS and images files) are traditionally put in a directory named OEBPS.

An example file structure:

--ZIP Container-- mimetype META-INF/   container.xml OEBPS/   content.opf   chapter1.xhtml   ch1-pic.png   css/     style.css     myfont.otf 

An example container.xml, given the above file structure:

<?xml version="1.0" encoding="UTF-8" ?><containerversion="1.0"xmlns="urn:oasis:names:tc:opendocument:xmlns:container"><rootfiles><rootfilefull-path="OEBPS/content.opf"media-type="application/oebps-package+xml"/></rootfiles></container>

Version 3.0.1

The EPUB 3.0 Recommended Specification was approved on 11 October 2011. On June 26, 2014 EPUB 3.0.1 was approved as a minor maintenance update to EPUB 3.0. EPUB 3.0 supersedes the previous release 2.0.1. [lower-alpha 5]

EPUB 3 consists of a set of four specifications: [20]

The EPUB 3.0 format was intended to address the following criticisms:

On June 26, 2014, the IDPF published EPUB 3.0.1 as a final Recommended Specification. [23]

In November 2014, EPUB 3.0 was published by the International Standards Organization as ISO/IEC TS 30135 (parts 1-7). [24]

In January 2020, EPUB 3.0.1 was published by the International Standards Organization as ISO/IEC 23736 (parts 1-6). [25]

Version 3.2

EPUB 3.2 was announced in 2018, [26] and the final specification was released in 2019. [27]


The format and many readers support the following:

Digital rights management

An EPUB file can optionally contain DRM as an additional layer, but it is not required by the specifications. [31] In addition, the specification does not name any particular DRM system to use, so publishers can choose a DRM scheme to their liking. However, future versions of EPUB (specifically OCF) may specify a format for DRM. [17]

The EPUB specification does not enforce or suggest a particular DRM scheme. This could affect the level of support for various DRM systems on devices and the portability of purchased e-books. Consequently, such DRM incompatibility may segment the EPUB format along the lines of DRM systems, undermining the advantages of a single standard format and confusing the consumer. [32] [33] [34] [35] [36] [37]

DRMed EPUB files must contain a file called rights.xml within the META-INF directory at the root level of the ZIP container. [17] [ clarification needed ]


EPUB is widely used on software readers such as Google Play Books on Android and Apple Books on iOS and macOS, but not by Amazon Kindle's e-readers or associated apps for other platforms. Kindle uses mainly the Mobipocket (MOBI) format, or their proprietary formats AZW, AZW3 or KFX. iBooks also supports the proprietary iBook format, which is based on the EPUB format but depends upon code from the iBooks app to function. [38]

Data interchange
EPUB is a popular format for ebook creation because it can be an open format and is based on HTML, as opposed to Amazon's proprietary format for Kindle readers. Popular EPUB producers of public domain and open licensed content include Project Gutenberg, PubMed Central, SciELO and others.


An EPUB file is an archive that contains, in effect, a website. It includes HTML files, images, CSS style sheets, and other assets. It also contains metadata. EPUB 3 is the latest version. By using HTML5, publications can contain video, audio, and interactivity, just like websites in web browsers. [29]


An ePub publication is delivered as a single file. This file is an unencrypted zipped archive containing a set of interrelated resources. [39]

An OCF (Open Container Format) Abstract Container defines a file system model for the contents of the container. The file system model uses a single common root directory for all contents in the container. All (non-remote) resources for publications are in the directory tree headed by the container's root directory, though EPUB mandates no specific file system structure for this. The file system model includes a mandatory directory named META-INF that is a direct child of the container's root directory. META-INF stores container.xml.

The first file in the archive must be the mimetype file. It must be unencrypted and uncompressed so that non-ZIP utilities can read the mimetype. The mimetype file must be an ASCII file that contains the string "application/epub+zip". This file provides a more reliable way for applications to identify the mimetype of the file than just the .epub extension. [39]

An example file structure:

--ZIP Container-- mimetype META-INF/   container.xml OEBPS/   content.opf   chapter1.xhtml   ch1-pic.png   css/     style.css     myfont.otf   toc.ncx 

There must be a META-INF directory containing container.xml. This file points to the file defining the contents of the book, the OPF file, though additional alternative rootfile elements are allowed. [39] Apart from mimetype and META-INF/container.xml, the other files (OPF, NCX, XHTML, CSS and images files) are traditionally put in a directory named OEBPS. An example container.xml:

<?xml version="1.0" encoding="UTF-8" ?><containerversion="1.0"xmlns="urn:oasis:names:tc:opendocument:xmlns:container"><rootfiles><rootfilefull-path="OEBPS/content.opf"media-type="application/oebps-package+xml"/></rootfiles></container>


The ePUB container must contain: [40]

The ePUB container may contain:


Content documents include: [41] HTML 5 content, navigation documents, SVG documents, scripted content documents, and fixed layout documents. Contents also include CSS and PLS documents. Navigation documents supersedes the NCX grammar used in EPUB 2.

Media overlays

Books with synchronized audio narration are created in EPUB 3 by using media overlay documents to describe the timing for the pre-recorded audio narration and how it relates to the EPUB Content Document markup. The file format for Media Overlays is defined as a subset of SMIL. [42]


Many editors exist including calibre and Sigil, both of which are open source. Another open source tool, called epubcheck, can be used for validating and detecting errors in the structural markup (OCF, OPF, OPS), image, and XHTML files. [43]

Readers exist for all major hardware platforms with the exception of Amazon Kindle, such as Adobe Digital Editions and calibre on desktop platforms, Google Play Books and Aldiko on Android and iOS, and Apple Books on macOS and iOS.

Reading software

The following software can read and display EPUB files:

Reading Systems and Software [19]
SoftwareLicensePlatformDRM formats supportedNotes
Adobe Digital Editions Proprietary Microsoft Windows, Apple Mac OS X Adobe Content Server Requires online activation for ePub files with DRM.
Aldiko ProprietaryAndroidAdobe Content ServerSupports ePub for Android devices.
Apple Books ProprietaryOS X, iOS FairPlay [44] Supports EPUB 2 and EPUB 3. Books not readable directly on computers other than Macs.
Bluefire Reader ProprietaryApple iOS, AndroidAdobe Content ServerSupports ePub for Android and iOS devices.
calibre GPL Windows, OS X, LinuxNonePrimarily for library management, conversion, and transferring to devices, it includes an EPUB reader and editor. "About". Calibre.
Microsoft Edge ProprietaryWindows 10Microsoft Edge will end support for e-books that use the .epub file extension over the next several months. "August 30, 2019—KB4512941".
FBReader ProprietaryWindows, Linux, Android, PDAs, OS XNone
Google Play Books ProprietaryWeb application, Android, Apple iOSLektz DRMSupports downloading purchased books as ePub and/or PDF.
Kitabu ProprietaryOS XNoneSupports ePub3, ePub2, Fixed layout.
Kobo ProprietaryWindows, OS X, Android, Apple iOS, Kobo eReader Software,Adobe Content ServerSupports EPUB 2 and EPUB 3.
Lektz Readers Proprietary Web application, Google Android, OS X, iOS, Windows Lektz eBook Readers for PDF, ePUB/2 and ePUB3 providing uniform experience across different platforms - iOS, Android, Windows PC, Mac Desktop and Web.
Lucifox GPL Windows, OS X, LinuxNoneEbook reader add-on with annotations for Firefox. Supports open standard ebooks in EPUB 3- and EPUB 2 format and retrieval of books from OPDS book catalogues.
Okular GPL Windows, OS X, Linux
Snapplify ProprietaryAll Web browsers, Apple iOS, AndroidAdobe Content Server Snapplify SnappSafe DRMSupports downloading purchased books as ePub and/or PDF. Supports PDF, ePUB2 and ePUB3 standard of ebooks.
STDU Viewer FreewareWindowsSupports many documents format including ePub.
Sumatra PDF GPL WindowsAdobe Content ServerSupports ePub for devices.

See also the Wikipedia category for articles about EPUB readers.

Editing software

Creation Software
ABBYY FineReader Microsoft WindowsProprietaryVersion 11 exports to EPUB format.
Abiword FreeBSD, Linux, Windows GPL Support EPUB 2.0 format export since 2.9.1 release [45]
Adobe InDesign Windows, OS XProprietaryExports to EPUB format. Versions prior to 5.5 create EPUBs that require significant editing to pass ePubCheck or ePubPreFlight. As from InDesign CC 2014, InDesign can export in ePub3 fixed-layout format.
Adobe RoboHelp WindowsUnknownOnline documentation tool that supports export to EPUB format
Atlantis Word Processor Windows, Portable app Shareware Converts any document to EPUB; supports multilevel TOCs, font embedding, and batch conversion.
Booktype Web GPL Book production platform that outputs to many formats, including ePub. The platform can import content in various formats and supports collaborative editing.
calibre Windows, OS X, FreeBSD, Linux GPL Conversion software and e-book organizer. Allows plugins, including for editing EPUB files; there is for instance a plugin to merge several EPUB files into one. [46]
Creative Book Builder Apple iOS , OS X, AndroidUnknownEditor on mobile devices that can import EPUB and export EPUB and PDF
eLML Windows, OS X, FreeBSD, LinuxUnknownThe eLesson Markup Language is a platform-independent XML-based open source framework to create eLearning content. It supports various output formats like SCORM, HTML, PDF and also eBooks based on the ePub format.
Feedbooks WebUnknownFree cloud service for downloading public domain works and for self-publishing.
Help & Manual WindowsProprietary Single source publishing tool that generates ePUB amongst several other documentation formats.
HelpNDoc WindowsFree for personal use, commercial otherwise.Help authoring tool that generates EPUB files and other formats.
iBooks Author OS XUnknown Desktop publishing and page layout application. Free from Apple. Can export .ibooks format, which is a proprietary format based on EPUB. [47] There are restrictions on the commercial distribution of works created with iBooks in the .ibooks format. [48] These restrictions apply to the .ibooks format only [49] and it can be argued that a file renamed to .epub is not distributed in the .ibooks format.
iStudio Publisher OS XProprietary Desktop publishing and page layout application.
LibreOffice Windows, OS X, Linux Mozilla Public License, GNU Lesser General Public License Text processor with a functionality to export as ePub3 format since version 6.0. Also allowed to export as ePub format via installing extension, such as eLaix. [50]
Lulu.com WebProprietaryConverts .doc, .docx, or PDF manuscripts to an ePub in order that they may be sold on the Website in question.
Madcap Flare WindowsProprietary Single source publishing tool that can export content as ePUB.
oXygen XML Editor OS X, Windows, FreeBSD, LinuxProprietaryoXygen XML Editor is the first tool that supports creating, transforming, and validating the documents that comprise the EPUB package.
Pages OS XUnknownWord processor (part of the iWork '09 suite) that can export to EPUB format (Pages '09 only, and only with the iWork 9.0.4 update).
Pages Apple iOS UnknownWord processor for mobile devices that can export to EPUB format
Pandoc Unix-like, WindowsGPLv2Can output EPUB Versions 2 and 3
Playwrite OS XProprietaryNative EPUB-based word processor. Native to EPUB 3 with EPUB 2 compatibility.
QuarkXPress OS X, WindowsProprietaryDesktop publishing tool, page layout application. Exports also to the ePUB format.
Serif PagePlus WindowsProprietaryDesktop publishing program that can export to the EPUB 2 and EPUB 3 format. Comes with built-in output conversion profiles for targeting specific devices, as well as generic devices. Also includes pre-tested blank eBook templates, or can open and edit existing PDF files and publish as EPUB.
Scrivener Windows, OS XProprietaryProgram for writers. Includes organization capabilities for fiction writers. Publishes to multiple formats.
Sigil Windows, FreeBSD, Linux, OS X GPL Can open and edit EPUB books, instead of just converting from other formats to EPUB. Since version 0.7, supports embedding video or audio in EPUB. [51]
eXeLearning Windows, Linux, OS X GPL Can be used to create educational interactive Web content, HTML5, IMS, SCORM and EPUB3 books [52]


  1. For a table of the required XHTML modules and a description of the restrictions, see "Section 2.2", ePub OPS 2.0.1 (specification draft), IDPF.
  2. For a table of supported properties and detailed information, see "Section 3.0", ePub OPS 2.0.1 (specification draft), IDPF.
  3. For a full listing of metadata, see "Section 2.2", ePub OPF 2.0.1 (specification draft), IDPF.
  4. A list of possible values for type is in "Section 2.6", ePub OPDF 2.0.1 (specification draft), IDPF.
  5. Detailed descriptions of the differences between 3.0 and 2.0.1 can be found on ePub 3.0 spec changes, IDPF.

Related Research Articles

HTML Hypertext Markup Language

Hypertext Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript.

An HTML element is a type of HTML document component, one of several types of HTML nodes. HTML document is composed of a tree of simple HTML nodes, such as text nodes, and HTML elements, which add semantics and formatting to parts of document. Each element can have HTML attributes specified. Elements can also have content, including other elements and text.

XML Linking Language, or XLink, is an XML markup language and W3C specification that provides methods for creating internal and external links within XML documents, and associating metadata with those links.

XInclude is a generic mechanism for merging XML documents, by writing inclusion tags in the "main" document to automatically include other documents or parts thereof. The resulting document becomes a single composite XML Information Set. The XInclude mechanism can be used to incorporate content from either XML files or non-XML text files.

XBRL Exchange format for business information

XBRL is a freely available and global framework for exchanging business information. XBRL allows the expression of semantic meaning commonly required in business reporting. The language is XML-based and uses the XML syntax and related XML technologies such as XML Schema, XLink, XPath, and Namespaces. One use of XBRL is to define and exchange financial information, such as a financial statement. The XBRL Specification is developed and published by XBRL International, Inc. (XII).

Open eBook, or formally, the Open eBook Publication Structure (OEBPS), is a legacy e-book format which has been superseded by the EPUB format. It was "based primarily on technology developed by SoftBook Press". and on XML. OEB was released with a free version belonging to public domain and a full version to be used with or without DRM by the publishing industry.

The Sitemaps protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. A Sitemap is an XML file that lists the URLs for a site. It allows webmasters to include additional information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs of the site. This allows search engines to crawl the site more efficiently and to find URLs that may be isolated from the rest of the site's content. The Sitemaps protocol is a URL inclusion protocol and complements robots.txt, a URL exclusion protocol.

This article describes the technical specifications of the OpenDocument office document standard, as developed by the OASIS industry consortium. A variety of organizations developed the standard publicly and make it publicly accessible, meaning it can be implemented by anyone without restriction. The OpenDocument format aims to provide an open alternative to proprietary document formats.

GRDDL is a markup format for Gleaning Resource Descriptions from Dialects of Languages. It is a W3C Recommendation, and enables users to obtain RDF triples out of XML documents, including XHTML. The GRDDL specification shows examples using XSLT, however it was intended to be abstract enough to allow for other implementations as well. It became a Recommendation on September 11, 2007.

RDFa is a W3C Recommendation that adds a set of attribute-level extensions to HTML, XHTML and various XML-based document types for embedding rich metadata within Web documents. The RDF data-model mapping enables its use for embedding RDF subject-predicate-object expressions within XHTML documents. It also enables the extraction of RDF model triples by compliant user agents.

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.

The Open Packaging Conventions (OPC) is a container-file technology initially created by Microsoft to store a combination of XML and non-XML files that together form a single entity such as an Open XML Paper Specification (OpenXPS) document. OPC-based file formats combine the advantages of leaving the independent file entities embedded in the document intact and resulting in much smaller files compared to normal use of XML.

The following is a comparison of e-book formats used to create and publish e-books.

eXtensible HyperText Markup Language (XHTML) is part of the family of XML markup languages. It mirrors or extends versions of the widely used HyperText Markup Language (HTML), the language in which Web pages are formulated.

XFrames is an XML format for combining and organizing web based documents together on a single webpage through the use of frames. Similarly to HTML Frames, XFrames can be made useful through its power to create a content frame that is scrollable while other frames - such as sidebar menus, the header and footer remain in place on the page. XFrames will be particularly useful to web developers who will be able to modify a single document and have that modification appear on all pages that contain the document within a frame.

The International Digital Publishing Forum (IDPF) was a trade and standards association for the digital publishing industry, set up to establish a standard for electronic book publishing. It was responsible for the EPUB standard currently used by most e-readers.

In computing, Open Data Protocol (OData) is an open protocol which allows the creation and consumption of queryable and interoperable RESTful APIs in a simple and standard way. Microsoft initiated OData in 2007. Versions 1.0, 2.0, and 3.0 are released under the Microsoft Open Specification Promise. Version 4.0 was standardized at OASIS, with a release in March 2014. In April 2015 OASIS submitted OData v4 and OData JSON Format v4 to ISO/IEC JTC 1 for approval as an international standard.

XHTML+RDFa is an extended version of the XHTML markup language for supporting RDF through a collection of attributes and processing rules in the form of well-formed XML documents. XHTML+RDFa is one of the techniques used to develop Semantic Web content by embedding rich semantic markup. Version 1.1 of the language is a superset of XHTML 1.1, integrating the attributes according to RDFa Core 1.1. In other words, it is an RDFa support through XHTML Modularization.

The Open Publication Distribution System (OPDS) catalog format is a syndication format for electronic publications based on Atom and HTTP. OPDS catalogs enable the aggregation, distribution, discovery, and acquisition of electronic publications. OPDS catalogs use existing or emergent open standards and conventions, with a priority on simplicity.


  1. "Specifications". IDPF. Archived from the original on July 6, 2017. Retrieved January 12, 2017.
  2. "OPS 2.0 Elevated to Official IDPF Standard". IDPF. eBooklyn. Oct 15, 2007.
  3. "Endorsement of EPUB 3". BISG. Book Industry Study Group. 2012-08-06. Archived from the original on 2016-04-17. Retrieved 2020-05-05.
  4. "The Different Ebook Formats Explained: EPUB, MOBI, AZW, IBA, and More".
  5. "Older Versions of EPUB | International Digital Publishing Forum". idpf.org. Archived from the original on 2017-08-31. Retrieved 2017-05-10.
  6. 1 2 "1.1 EPUB Revision History". IDPF. 11 October 2011.
  7. "EPUB 3.0 | International Digital Publishing Forum". idpf.org. Archived from the original on 2012-04-17. Retrieved 2017-01-12.
  8. 1 2 Rothman, David (July 27, 2008). "The ePub torture test: Starring 'Three Shadows,' a graphic novel". TeleRead: Bring the E-Books Home.
  9. "EPUB 3.1 | International Digital Publishing Forum". idpf.org. Archived from the original on 2017-07-06. Retrieved 2017-01-12.
  10. "EPUB 3.1 Changes from EPUB 3.0.1". www.idpf.org. Retrieved 2017-01-12.
  11. "EPUB 3.1 Changes from EPUB 3.0.1". www.idpf.org. Retrieved 2017-01-12.
  12. "EPUB 3.1 Changes from EPUB 3.0.1". www.idpf.org. Retrieved 2017-01-12.
  13. "IDPF Members Approve W3C Merger - Publishing Perspectives". 9 November 2016.
  14. "World Wide Web Consortium (W3C) and International Digital Publishing Forum (IDPF) Explore Plans to Combine".
  15. 1 2 3 4 5 6 "Open Publication Structure (OPS) 2.0.1 – Recommended Specification". IDPF. September 4, 2010. Retrieved February 21, 2011.
  16. 1 2 3 4 5 6 7 8 "Open Packaging Format (OPF) 2.0.1 – Recommended Specification". IDPF. September 4, 2010. Retrieved February 21, 2011.
  17. 1 2 3 4 5 "Open Container Format (OCF) 2.0.1 – Recommended Specification". IDPF. September 4, 2010. Retrieved February 21, 2011.
  18. 1 2 "Specifications for the Digital Talking Book". NISO. April 21, 2005. Archived from the original on August 31, 2009. Retrieved October 9, 2009.
  19. 1 2 "EPUB 101" (PDF). eBook Technologies. Retrieved 10 July 2014.
  20. "EPUB 3 Overview Draft". EPUB 3 Working Group. IDPF. 11 October 2011. Archived from the original on 15 April 2012. Retrieved 11 October 2011.
  21. "Links, pointers, bookmarks, highlights: How should .epub do it?". FrontMatters. BookGlutton. March 29, 2008.
  22. Rothman, David (November 5, 2007). "'Social annotation and the marketplace of ideas': Time for an IDPF annotation standard for books and other e-pubs!". TeleRead: Bring the E-Books Home. Archived from the original on January 13, 2013. Retrieved October 8, 2009.
  23. EPUB 3.0.1 Changes, IDPF, retrieved July 8, 2014.
  24. EPUB 3.0 Published as ISO Technical Specification, IDPF, retrieved August 28, 2018.
  25. New and Emerging Specs and Standards (March 2020), NISO, retrieved April 11, 2020.
  26. "EPUB 3.2 Rationale". 11 April 2020. Retrieved 2020-05-07.
  27. "EPUB 3.2". W3C. Retrieved 2020-05-07.
  28. "Fixed-Layout Properties". International Digital Publishing Forum. Retrieved 11 September 2015.
  29. 1 2 "Understanding EPUB 3". EPUBZone. International Digital Publishing Forum. Retrieved 11 September 2015.
  30. "Embedded MathML". IDPF. Retrieved 12 September 2015.
  31. 1 2 "Digital Book Standards FAQs". IDPF. November 20, 2006. Archived from the original on 2009-09-03.
  32. Gelles, David (January 29, 2010). "Walls close in on e-book garden". The Financial Times.
  33. Rothman, David (August 13, 2009). "Adobe-DRMed ePub isn't 'open': Why the New York Times urgently needs to clarify its Sony eBook Store article". TeleRead: Bring the E-Books Home. Archived from the original on October 14, 2009.
  34. Biba, Paul (December 21, 2009). "Does the Nook use its own incompatible DRM scheme?". TeleRead: Bring the E-Books Home. Archived from the original on December 28, 2009. Retrieved January 29, 2010.
  35. Biba, Paul (January 28, 2010). "iPad adds to the DRM mess? Apple ebook DRM exclusive to Apple hardware". TeleRead: Bring the E-Books Home. Archived from the original on February 2, 2010. Retrieved January 29, 2010.
  36. Kendrick, James (January 28, 2010). "Who Really Needs an iPad?". JK On The Run.
  37. Dickson, Dave (January 27, 2010). "EPUB, iPad and Content Interoperability". Digital Editions. Adobe.
  38. Arnold Kim (January 19, 2012). "New ibooks not technically in epub format". MacRumors.
  39. 1 2 3 "EPUB Open Container Format (OCF) 3.0 – Recommended Specification". IDPF. Retrieved 11 September 2015.
  40. "EPUB Publications". IDPF. Retrieved 12 September 2015.
  41. "EPUB Content Documents". IDPF. Retrieved 12 September 2015.
  42. "EPUB Media Overlays". IDPF. Retrieved 12 September 2015.
  43. "GitHub - w3c/epubcheck: Validation tool for EPUB". 9 February 2019 via GitHub.
  44. Pham, Alex (February 15, 2010). "Apple to wrap digital books in FairPlay copy protection". The Los Angeles Times.
  45. 2.9.1 release notes, Abi source.
  46. JimmXinu. "GUI Plugin: EpubMerge". MobileRead Forums. Retrieved 24 February 2012.
  47. Bott, Ed (January 22, 2012). "How Apple is sabotaging an open standard for digital books". ZDNet. Retrieved January 30, 2012.
  48. "iBooks Author FAQ". Apple. March 23, 2012. Retrieved April 26, 2012.
  49. "Apple iBooks Author FAQ". Apple. March 23, 2012. Retrieved April 26, 2012.
  50. "eLaix", Extension center, Libre Office.
  51. Sigil dev .
  52. eXeLearning .