Converting From InDesign to Kindle
The following is an excerpt from the feature article, "From InDesign to Kindle" by Kevin Callahan, in the April 2015 issue of InDesign Magazine. Learn more from Kevin about publishing to Kindle in his session at PePcon: the Print + ePublishing Conference.
As Callahan explains in this feature story, Adobe InDesign can't export directly to the proprietary Kindle ebook format (KF8/Mobi), but it can export to the open source industry standard EPUB format used by iBooks, Kobo, and other eReader software. The good news is that Amazon offers a free EPUB-to-Kindle converter utility called Kindle Previewer.
So, the basic InDesign to Kindle workflow is to export the INDD file to EPUB (Reflowable), edit the contents of the EPUB file to optimize the markup for KF8, then convert the modified EPUB to KF8 format with Kindle Previewer. Following are some of the edits that Callahan suggests you might want to make to the EPUB file before converting it to Kindle.
There are some differences between the display of features in reflowable EPUB and Kindle environments. You'll need to dig into your exported EPUB to check on a few specific elements before it's ready for KF8 creation.
To do this work, you'll need access to the files inside an EPUB. If you're working in Windows, change the name of the file from book.epub to book.zip and unzip it. If you're on a Mac, you'll need a utility like ePub Zip-Unzip (available from the MobileReads forum, an essential resource on most things ebooks).
Once you've cracked open the EPUB you'll have access to the XHTML and CSS files. I use either TextWrangler or Dreamweaver to edit. If you want to work within the zipped EPUB, oXygen Author and BBEdit open an EPUB without unzipping it. Sigil is a similar (and free) choice, but it doesn't currently support EPUB 3.