A short note on formats eBook is a digital version of a which could be in any of the following formats – PDF, , mobi, PDB, TXT, LRF, CHM, djvu, LIT, etc. ePub format is supported by Android devices, Apple devices, Barnes & Noble Nook, , Kobo, SonyReader, etc. Kindle (mobi format) files are supported by Kindle devices, Apple iOS devices and Android devices.

Your Question: What is Epub3? Are you using it? Is it true that this format will work perfectly on ALL devices?

Our Answer: ePUB 3 is the newest revision of the ePUB standard. ePUB 3, once the standards are finalized and eBook readers become compatible with this new standards, will support Rich Media Enhancements (video and audio support, synchronization of audio with text, embedded font support, improved SVG support, JavaScript support) and General Enhancements (latest web standards - HTML5/CSS3, global language support – vertical writing, style and layout enhancements – multi-columns, hyphenation, and MathML support). International Digital Publishing Forum’s ePUB 3 working group is currently working on finalization of standards and validations.

We are yet to start producing ePUB 3 because the standards are yet to be finalized and currently there are no reading devices supporting ePUB 3.

At this point in time, we do not know if all eReaders will support all features of ePUB 3.

Your Question: Are you able to ensure that TOC appears on ePUB files in future? Currently not working on generic ePub files when uploaded to Kindle.

Our Answer: Yes. We have ensured that TOC appears when you open an ePUB file in Kindle Previewer which converts the ePUB into a .mobi file.

Your Question: Can you send an ePub format file that is optimised for Kindle?

Our Answer: Kindle uses .mobi format files which are created according to the specifications of Kindle Formatting Guidelines. Likewise, Apple’s iBookstore has its own specifications (in addition to IDPF’s ePUB standards) which are pertinent to sell the ePUB files through their iBookstore to be used on iBooks on iPad device. Other readers like Barnes & Noble and also support ePUB files but they mostly comply with IDPF specifications.

Kindle does not support .epub format per se but converts an ePUB file into Kindle compatible mobi file which can be opened in Kindle devices and Kindle Previewer. However, such conversion is advisable only for fictions, novels, and text driven content which contains less number of layout styles, formatting and with images where alignment is not an issue.

One can convert an epub file into mobi format and view it on Kindle device but any special formatting done in ePub files will be lost due to limited compatibility with CSS.

There would be some differences in formatting, places where KindleGen (ePub to Mobi convertor) misinterprets/ignores complex CSS instructions. Due the real estate of the device, images will be rendered incorrect or fuzzy. Images will be automatically re-sized by KindleGen. The kindle internally supports JPEG and GIF images of up to 63KB in size.

We recommend creating separate eBook for Kindle (.mobi), Apple (iBook specific ePub) and other devices (ePub). Although theoretically these file formats can be converted vice versa, formatting and good reading experience will be lost.

Your Question: If we ask you to create an ePUb file that is optimized for Kindle, will it still work on other devices?

Our Answer: As mentioned earlier, we are delivering ePub files which can be opened in Kindle Previewer, but these files wouldn’t follow Kindle Formatting Guidelines. We recommend creating separate eBook for Kindle (.mobi), Apple Store (iBook specific ePub) and other devices (ePub).