Sell me on KOReader

[radius]

I'm looking for an epub reading app for my (LCD-display) Android tablet. Once upon a time I used to use Aldiko but I was never in love with it.

I've seen the hoops people jump through to install KOReader on their Kindles and Kobos so I thought there must be something great about it to inspire such loyalty and motivate people to replace perfectly serviceable, built-in software.

But after installing it, I feel like I am using Athena-widget, GNU software from the 1990s. I guess maybe the UI is optimized for eink displays. But in any case, I don't understand the appeal yet.

What am I missing?

[pazos]

Originally Posted by radius

What am I missing?

Purpose

Give readest a try, read as much as you want. If you somehow feel like you want to read on a platform readest doesn't support install KOReader in there and sync everything.

Most of us who use KOReader on lcd devices is because we're also using it on eink and we are so within the ecosystem we would miss a lot by not using it

But that's probably NOT your case, spetially if you consider stock options "perfectly serviceable"

[xor_]

Because it's free software, and I think it's important to have an eco-system of open source software. Also, the developers are pretty cool.

One initial appeal was that it had PDF reflow and better font support.

Back when I started using it, the project was Kindle-only software. And part of the appeal was to join the effort to get it running on Kobos in the first place. Today there are no hoops to jump through.

I also don't mind the somewhat arcane interface. And I actually had to check whether my Emacs was still using Athena widgets. I guess it doesn't.

[Ebookus]

Originally Posted by radius

perfectly serviceable, built-in software.

stick with stock then. nothing wrong with that.

[Jellby]

* You can use the same software on different readers.

* There's a good chance you can configure it to your liking: If it's not there, you may raise a feature request or implement it yourself.

[neil_swann80]

Koreader seemed incredibly convoluted to me at first, but it's my daily driver for reading on my Pocketbook and Android devices now. There is a steep-ish learning curve to get everything setup to your liking, but worthwhile IMHO.

The Kosync feature to sync book progress and cloud integration (I use Dropbox) to effortlessly sync ebooks across my devices make it essential for me. I can obtain ebooks directly on any of my Koreader devices and sync them to my other devices without using a PC as an intermediary.

Being able to set a system default font and format to my preference within Koreader so every book is visually consistent without need for Calibre tweaking is a godsend for my use case.

Koreader allows you to drastically customize the look and feel of the display. I prefer my reading interface to be as minimalist as possible, just the text on screen; no progress bars, page numbers, status bars, clock or battery meters etc. I can tap on the bottom of the screen to un-hide a status bar (also customizable) should I wish to.

I can set gestures to various screen corner taps (or long presses, multi-finger swipes) to quickly toggle or activate certain features; e.g. dark mode, backlight, touch screen, reading stats, bookmarks, highlights, manual progress push/pull... just the few I use, many more beyond that.

There is also a wealth of optional plugins you can add. There's a particularly good NY Times Crossword plugin available as well as a Text-to-Speech plugin in development.

Koreader supports the StarDict dictionary format, so you have plenty of free and excellent dictionaries to choose from. I really like the dictionaries HERE.

Some people have reported faster battery depletion running Koreader on their devices, so keep an eye on that; I have not experienced this myself.

[Gormagon]

I tried different ereader apps on Android over the years and stuck with 2 of them: Librera and KOReader. Both have advantages and disadvantages.
Librera is faster than KOReader loading the oberview of all books if you have >2000 ebook files in one folder. The navigation between all books, recent and folders is also better on Librera.

The main advantage of KOReader for me is that the dictionary function using dz and idx files is already included. On Librera I have to use another app (usually GoldenDict) for this. Plus on KOReader I can add a word in the dictionary popup to the vocabulary builder with a click.

The UI of KOReader is not very intuitive for me. After some years, sometimes I still search quite long for certain settings. On the one hand you can set almost everything to your liking, on the other hand there are much to much options to remember exactly where they are. Since I just like to read text justified with font size, line height and other things adjusted to the size of the screen that's something I can also easily do in Libera much faster than in KOReader. Librera also has PDF reflow.

There are plugins and patches to improve KOReader. I use Project Title for an improved cover display plus the patch 2-reader-header.lua for a better status bar in the header.

What I don't like about KOReader is that for every book a sdr folder is created where a metadata.lua is stored. I know it's the file that stores your adjustments, bookmarks and so on for the book. Nevertheless it sucks to have so many folders with just one or two files (.lua + lua.old).

[radius]

Thanks for all the (in-depth!) replies. This was super valuable for me. Much appreciated.

[oleasteo]

For me, the main reasons to get it onto my Kindle are the multitude of small flaws of the built-in firmware:
- No folder structure for documents
- Pollutes "my" library with audible stuff I don't want to see; the option to hide audible doesn't work
- Selection (mainly for translation) of words doesn't consider m-dash as word separator, so there was no possibility to find a translation of a word that is written before/after a m-dash
- Pictures in books (e.g., world maps) sometimes are tiny, unreadable

In addition, now, I value
- Customizability of the status bar while reading, with actual useful info (e.g., floating point reading percentages)
- Custom wallpapers
- SSH connection; no more USB necessary
- Better ergonomics (customizable tap actions, one-handed lock screen, etc.)

I don't recall anything that the Kindle OEM does a better job with, once you've made the device your own. Yes, the UI feels like old-school GTK software, but it's superior in the things that matter.

Originally Posted by Gormagon

What I don't like about KOReader is that for every book a sdr folder is created where a metadata.lua is stored. I know it's the file that stores your adjustments, bookmarks and so on for the book. Nevertheless it sucks to have so many folders with just one or two files (.lua + lua.old).

Settings -> Document -> Book metadata location

[Gormagon]

Originally Posted by oleasteo

Settings -> Document -> Book metadata location

Yes, I already discovered this option, but that still creates countless folder/files - only in another location and using the internal memory of the device.

[JSWolf]

We can sell you on KOReader for a low low price of only $49.99.

[neil_swann80]

Originally Posted by Gormagon

Yes, I already discovered this option, but that still creates countless folder/files - only in another location and using the internal memory of the device.

It does, but assigning them to a specific directory makes purging them between books a triviality.

Librera is great if you're Android only, if you want something cross-platform Koreader is your best choice.

[Winston Payne]

I come from other ereader ecosystems/reading software, so potentially this doesn't apply to all of Android's other ereading apps, but in my case the biggest drivers towards KOReader were a love for good typography, being able to tinker with how text is displayed, and being able to run multiple dictionaries seamlessly.

On the typography front, it's stunning to me that in 2026 Kobo still doesn't support kerning or ligatures properly (two very basic features I consider essential) unless you want to mess around with hidden config files or changing the technical aspects of the font behind the scenes (such as by re-saving font files with legacy kern tables), and doesn't support small capitals at all (it fakes them, rather than using true small caps if a font has them); KOReader does all of that out of the box. Most ereading apps also offer zero control over font hinting, which drives me nuts, given that I read on high DPI ereaders (other apps tend to use autohinting, which often, but not always, looks terrible). With KOReader, I can disable the hinting altogether and use fonts as the creators intended.

KOReader is also great for QOL. I love not to needing to worry about converting my EPUB files to use them. I love being able to set margins, paragraph spacing, etc as wide or narrow as I darn well please (not as wide or narrow as Amazon/Kobo/etc think I should). I love being able to search multiple dictionaries at once and be able to quickly switch between them. I love being able to create custom actions by pushing corners of my screen and the ability to create custom gestures. On the rare occasions I don't like how the engine renders text (by default, it doesn't indent lists, for example), I can create custom CSS to tweak it. The list goes on and on.