Accepted formats and choosing EPUB

Why choose the .ePub format

We highly recommend the .ePub format because it is supported by most devices and reading apps. Since 2007, .ePub has been the official standard of the International Digital Publishing Forum (

The main advantage is that it is “ reflowable”. In simple terms, the flow of text is optimized and adapted to the display device and settings. This means that all your readers will have the optimum reading experience, whatever their device. For more information, visit and

There is also a Fixed Layout ePub, for books like comics or children books that need a fixed disposition in pages.

The accessible ePub is instead the format that all ebooks published as novelties must have. Specifically, for this type of ePub you will need: images accompanied by an alternative text description; functions accessible from keyboard and touch screen; a simple and sequential structure (to avoid, for example, presenting a text that overlaps the images or enclosed in blocks, arranged in a non-consequential way) and a content that is accessible over time: the reader must be able to easily use the ePub at the beyond technological innovations, the evolution of browsers, etc. The content must be readable in various applications, including assistive applications. Find more info here.

We also recommend the .ePub format because eBooks sold in PDF format could be not accepted by major stores.

So now you're convinced you want an ePub file, how can you get it?

There are 3 ways:

  1. You can create your own ePub eBook using StreetLib Write, the authoring tool to produce digital publishing content independently. Simply write your book with the editor of your choice (e.g. Word), sign up at, and build a professional-quality EPUB file. StreetLib Write requires no expert knowledge or skills of the software or formats.
  2. Alternatively, you can ask for the conversion from StreetLib Ready.
  3. You can create your ePub file using software such as InDesign, Calibre, or Sigil (if you are familiar with html and CSS coding). In this case, please be aware:
  • We do not recommend building an ePub file using the tool provided by Google Docs because it will create an ePub that is not valid for sale and that cannot be used for publication. We do not recommend using automatic conversion tools provided by text editing software in general.
  • The fonts used in EPUBs can be easily extracted, therefore they must be license-free. In the case of licensed fonts, we suggest that you check what the license terms of use for digital files are.
  •  If you decide to use InDesign or Calibre, please pay attention to all the technical details, but most importantly please make sure that the final ePub file is VALID from a structural point of view. Please remember that the ePub you upload must be validated by the ePubCheck tool.

Create your ePub independently

You can create your ePub using software like InDesign, Calibre or Sigil - to use the latter, you need confidence managing html and CSS codes. We do not recommend creating your ePub using the tool provided by Google Docs, because it creates an ePub that is not valid for sale, and which can't be used for publication. In general, we do not recommend any of the automatic conversions available with editing software that is not designed for publication purposes.
Fonts used within ePubs files, as they are easily extractable, must be license-free. In the case of licensed fonts, we suggest you check what the license requires for the use of digital files.
If you proceed with InDesign or Calibre, you will need to make sure that the final ePub file is VALID from a structural point of view, as the formatting may change.

How can you validate an ePub?

StreetLib only distributes ePubs that pass the EPubCheck validation, according to the IDPF standard. Validation must be done with the software EPubCheck, available at GitHub:

How can you validate an EPUB for Amazon?

For ePub reflowable, you will need to upload only the ePub format to Hub. Then Amazon will automatically generate the mobi file starting from the ePub that you uploaded to Hub and that we can send to the store. To make sure that Amazon can convert your ePub to mobi format, we suggest opening the ePub file with Kindle Previewer. Kindle Previewer will provide you with an overview of the book and will allow you to quickly verify the general layout. If the ePub file is not suitable for conversion for publication on Kindle, the application will show you an error message and will provide a detailed report of the issues that need to be fixed.

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