This is an overview of the current formats of digital books, from the EPUB to the enhanced ebooks and then the book app. By focusing on the formats, we can identify the format limitations and understand the differences between enhanced ebook offerings vs book apps.

Traditional Ebooks


EPUB is the most widely supported XML-based (as opposed to PDF) e-book format due to its open standards and being vendor-independent.

Before, ebooks came basically in two formats: the open standards EPUB, published by the International Digital Publishing Forum (IDPF), and Kindle (also known as mobi or AZW). These formats are known for their signature reflowable text that wraps accordingly based on the reading device from dedicated e-readers (Kindle, Nook, Kobo) as well as devices such as tablets and smartphones.

Historically, both EPUB and Kindle can trace its origins back to a 1999 industry initiative called the Open Ebook format. It was only until 2007 that EPUB took off in its release of version 2, a couple months before the Kindle’s launch. Following these events was an explosion in the ebook market that continues even today.

In many cases, such as for pure print works with simple formatting, the older EPUB and Kindle formats are the best option. They are the simplest to produce, easy to convert, and can be distributed to a large market. You can go from a Word (DOC) file and then have it converted and uploaded and distributed to Kindle, Kobo, and iBookstore in a snap.

However, EPUB and Kindle are constrained in formatting options and ways to enhance the readers’ experience.

Enhanced Ebooks

Enhanced ebooks go beyond the simple layout to include complex formatting, illustrations, multimedia content such as video and audio, and limited interactions. Mostly notably children’s books and textbooks have benefited from these features. In particular, we will look at EPUB 3, Kindle KF8, and Apple’s iBook formats.


In 2011, EPUB 3 was released by the IDPF to address some of the restrictions of the prior EPUB format. EPUB 3 supports the latest web standards that is HTML5, CSS3, and Javascript. Among the features of EPUB 3 are fixed width layouts, embedded multimedia, synchronized text and audio, improved formatting capabilities, and scripting interactivity.

Popular software to export to EPUB 3 include inDesign and iBook Author. For EPUB 3, inDesign would be the better choice as any 3 party widgets you may have for in iBook Author will not be exported. Furthermore, you have some scripting capabilities (using events and states), that iBook Author does not have.

Kindle KF8

Kindle KF8 (Kindle Format 8) replaced the .mobi format and features support for fixed-width layouts, CSS, video and audio, and improved formatting capabilities. There is no scripting interactivity support yet.

Recently, Kindle has rolled out its Kindle Kids’ Book Creator to allow easy creation and publication of children’s books with the fixed-width layouts.

Apple iBook

Apple iBooks 2 has been the most innovative on the interactive book scene with its own maker iBook Author. Built on EPUB 3, iBooks 2 released in 2012 aimed at the textbook market and has all the features with EPUB 3 with the added benefit of making it easier to embed widgets into your book. Similar to Kindle’s KF8, Apple’s .ibook format locks down the format to the distributor (Apple’s iBookstore vs Amazon’s Kindle). The only way to create an Apple iBook is through using their authoring tool, iBook Author which requires OSX.

More on enhanced ebook makers, 3 party widgets, and distribution channels on another post.

Book Apps

Book apps, like any app, can be categorized into native mobile apps, web apps, and hybrid apps.

Native mobile apps

Native mobile apps are basically apps that live on the app store made specifically for an operating system (usually iOS or Android). They have the ability to access hardware and application features of the device such as location, accelerometer, camera, etc. They are the most performant but also require higher costs to develop a separate app for each mobile platform. Nosy Crow, children's interactive book publisher, develops native iOS apps like Jack and the Beanstalk which uses non-linear dialogue in their stories.

web applications

Web apps integrate presentation, application logic, and storage.

Web apps

Web apps on the other hand live in your browser. They are written in HTML5 and can be read on any device or web browser which drastically cuts developmental costs. HTML5 has also developed quite rapidly. PBS Kids uses HTML5 to create vocabulary rich storybook adventures. Sketchfab uses HTML5 to share really awesome 3d models.

Hybrid apps

Hybrid apps bring web apps to the app store. They wrap the web app code using tools (like PhoneGap or Cordova). Therefore, hybrid apps only require one set of code to distribute to the different platforms, but are less performant. Since they live on the app store and can be downloaded to your device, they also have access to hardware and application features (through plugins instead of native).

Differences between enhanced ebooks and book apps

EPUB 3’s support of the latest web standards (HTML5, CSS3, and Javascript) may make it look very similar to a web app, but it is not. While web apps utilize the browser (Chrome, Safari, Microsoft Edge) to read, EPUB 3 is reliant upon a reader application (such as iBooks, Kobo Reader, Readium, Nook Apps, etc). Unfortunately, there are many factors that can influence the reading experience. The device may not support the reader. The reader application may not support all the features. The reader application is reliant on the browser to render certain features.

web app to read

Web apps only depend on the browser for rendering.

epub3 to read

The distribution of an EPUB 3 to the end user has more intermediaries.

Innovation with EPUB 3 is stagnant

There is little documentation on how to implement features in EPUB 3, leading those who want to develop from scratch hesitant to proceed. EPUB 3 is therefore heavily reliant on using the existing software InDesign and iBook Author, both which have little to no scripting ability. 

Furthermore, since the work is contained within these authoring tools, EPUB 3 lacks the core features considered standard in today’s technology such communicating to a database or connecting to social networks.

To add custom features (read-a-long, animation support, etc) then requires 3rd party widgets embedded inside iBook Author/InDesign. However, authoring tool may pose restrictions on exporting your enhanced book. Additional features from 3rd party widgets embedded into iBook Author are not exported to EPUB 3. It is possible to develop your own enhanced ebook using 3rd party widgets that enriches the interactions and features. See books like The Mozart Project. However, it will not have as much potential as a book app due to the packaging constraints.

Apps are unrestricted in their capabilities

In comparison, there are more documentation and frameworks for creating apps. Game development engines like Unity can also be a good starting point. Since you have full control over the code, apps are almost unrestricted in their capabilities. Apps can communication to a database to store information from how long a user has stayed on a page to the answer a user has selected on a quiz. Furthermore if it is a web app, the reading experience will also be the same across all devices on modern web browsers

The Future: Digital Book Apps

We are already seeing a push for making apps for digital content. Primarily, this trend has been escalating in higher education and marketing since apps have the ability to collect data for analysis. However, we will also see this expanding into enterprise training (like in the case of Inkling), magazines with integrated e-commerce, among K-12 education, and more.

Unfortunately, the cost of resources for creating book apps are still quite high. Alongside the content creation, you will need a development team that can code and distribute your book app. Elementari solves this by packaging the technology for individuals and small organizations to easily create, share, and analyze their book app. Contact us for more details.