The InDesign Fixed-Layout ePub —> Kindle Dilemma

That content is not inaccurate, but it's rather outdated and coming from a party that is both highly interested and frustratingly disinterested... which would take too much time to explain here.

The first of two crucial takeaways here is that hardly any two EPUB readers manage the format and its presentation the same way. There is a standard, frequently updated (these days, largely with nits about accessibility, with no attention paid to major faults and needs for upgrade), but there is not even a weak enforcing body or one with enough "gravity" to pull reader developers into a common orbit. That your exports work on Apple is very mildly surprising; while their reader is fairly standard, Apple follows its general principle of doing things "differently and better." They at least have the engineering muscle to to things right as far as code quality and product testing. Many of the other readers come from very small shops, if not solo developers, and incorporate every quirk the maker can think of, often with minimal stability and compatibility testing.

Put another way, EPUB is not as much a standard as a concept, and issuing works in it mean every single user will have a different experience, depending on their reader/app, its settings, their preferences, minor variations in the EPUB file itself and sometimes (it seems) just the phase of the moon. Set aside the idea that there is some body of "working" platforms and a few outliers; besides a few pure, standard-driven, vanilla readers, they are all outliers. Kindle is actually the best technical solution because it's a closed ecosystem, much like Apple technology, and if something is there, it works. But conversion from outside docs is... unpredictable and the conversion process is wholly undocumented. So again, you need to set aside the idea that you can somehow do "perfect" EPUBs and it's _________'s fault if one doesn't work there — you can only optimize your docs for each platform and let the chips fall for any user who uses some other app or reader.

The other takeaway is that the production tools only take the job so far. There is no perfect EPUB generator. It's not like using InDesign to PDF to a print service, where zero outside (or "internal") knowledge is needed; just use the app right and all will shine. But with a fragile, mishandled format like EPUB, InDesign (for example) does its best, but that 'best' has limits not addressable from within the app, and a truly superior result requires skills and knowledge outside the menu-driven interface.

You can remain an "old school designer" — my experience goes back to blueline boards and wax pasteup — and decline to learn new skills, but that leaves you at the mercy of what platforms and what file types work within a narrow range of erratic alternatives. Your book — even in FXL — is likely fixable to Kindle-import standards, but not (most likely) with anything to be found in an InDesign menu, or even in the menu-driven EPUB editors. It's just a world where success means knowing more than what key combination to press. 🙂

Maybe one day we'll get a real e-doc format, one more flexible (literally) than PDF. But for now, EPUB v3 rules, and does so badly.

EPUB =/= PDF =/= Kindle. It's that simple. Three different formats, generated under three different sets of standards. And for Kindle, since there is no good way to directly generate their format, it's all up to how they choose to handle conversion from other formats.

You're looking at it a bit backwards, to tell the truth. FXL is and always has been a fairly substandard format. That it works on some platforms is more the anomaly than not working on another.

As for then and now, the platforms and the readers are continually evolving. That one (so far) has evolved away from 'perfect' support of this largely obsolete format is unsurprising. Kindle has moved forward with a more capable format, overall, and has deprecated most of what came before, including its original MOBI format. It does not support EPUB directly, despite some marketing razzle-dazzle; it converts EPUB to its own current proprietary format whether it announces the fact or not. (Such as the supposed big deal of being able to side-load EPUBs; they aren't EPUB on the device.)

It's possible your book could be tweaked into better Kindle compliance, but again, one of FXL's weaknesses is that it is very difficult to work with once generated. If you're not familiar with the structure, reflowable EPUB is basically a packaged web site; a flowing text file with some markup that is presented, in liquid form, according to style rules. You can edit both the text and the styles pretty easily, if you have a little bit of HTML/CSS knowledge. FXL is... <giant gob of code; put an 'e' here><giant gob of code; put a 't' here><giant gob... well, you get it. A wonky, fragile, overwrought method to "paint" a page on the screen. Thus, it was always strongest for picture-based pages like children's books and comics, rather than positioning hundreds of characters on a screen, one at a time like a Lite-Brite.

I assure you that no 'fix' is coming from any direction. If you can't generate an adequate FXL file now, tomorrow will just be more so as the readers and platforms continue to evolve away from it.

Learn reflowable export, and how much can be done with it once things like CSS style control is mastered. It is not limited to streaming body text, as almost any of my published books will show.