HN Reader

KOReader is an amazing program that has progressed at amazing speed over the past few years, particularly when it comes to the user interface. (It can still be overwhelming, because of the sheer number of features, but it is much better organized.)

To give you an idea of how different it is from commercial products: it actually tracks reading in a useful way. It shows a chart of how long you have spent on each page, so you can figure out which parts of a book you have not yet read. That is really useful when jumping around technical books. If you are interested in tracking your general reading habits, there are handy views that shows which books you have read and when you read them (either by time of day or across a month).

As for reading PDFs, well, eInk has its limitations and KOReader does it's best to work around them. If you want to read a multicolumn paper on a small screen, you can configure it to go down one column then right back to the top of the next column. If you want there to be overlap between the screens when panning, you can configure that. You can also have it display which parts were overlapping, so you don't get lost when it displays the next part.

There is tonnes of other stuff in there. I just mentioned those two because I use them the most. Overall I would say it feels like KOReader was designed by people who want an amazing reading experience, rather than by people trying to sell novels.

Very impressive how the almost the entire application is written in lua(JIT). Particularly impressive how it is fast enough to do CPU blitting/blending[0]

I wonder why is lua so rarely utilized like this on its own. Such a neat language.

[0]: https://github.com/koreader/koreader-base/blob/master/ffi/bl...

Instead of simply praising KOReader, let me add that it is also incredibly hackable. The vast majority of KOReader is written in Lua, and adding your own feature is usually not that hard. I added support for Kobo natural light a few years ago, and found the code base to be very understandable and nice to work with.

I wish it supported vertical text and reading right-to-left (Japanese). It's a long-standing issue that doesn't seem likely to be solved (https://github.com/koreader/koreader/issues/4353). The relevant standard is https://www.w3.org/TR/css-writing-modes-3/, which is part of supporting ePub 3.

I wonder if load times have improved. I had this on my Kobo Libra 2, and it took it easily 5 minutes or more to open an admittedly large epub file. Changing the font size also incurred a huge penalty as it reflowed the entire document.

Conversely, the built-in software never struggled with that file.

Can anyone recommend a site for buying DRM free books so I can read it with KOReader?

Absolutely love KOReader. I use it on my Kindle 3 and have moved my parents and brother over to using it on their Kindles as well. You can even install it on relatively new models thanks to the recent WinterBreak gaolbreak.

There was some discussion about it on HN not long ago:

All Kindles can now be jailbroken | 1377 points by lumerina | 2025/02/17 | https://news.ycombinator.com/item?id=43073969

I found KOReader's Android app a tad buggy, but the experience is wonderful on Kindles. If you've got an old Kindle kicking around, I also wrote up a little thing about bringing them up to speed which mentions KOReader: https://vale.rocks/posts/improving-early-kindles

The ability of KOReader to infer panel boundaries to do intelligent panel zoom sounds like a nice feature. I wish other Android-available comic readers could do it. I've held onto Amazon's Kindle/Comixology app for much longer than I should because intelligent panel navigation is frequently a necessity, even on my 10" tablet.

For people on Kobo: Koreader handles standard epub way better than the native reader.

If you've ever tried reading an epub using Kobo that you didn't buy from the Kobo store, you may have noticed that highlighting text is very laggy. Koreader has no such lag.

Fair warning to those who are interested. If you are the kind of person who gets lost dabbling in configuration and customisation Koreader will keep you very busy with that. Once you get past that it is very worth it if you aren't tethered to your ereader's book store ecosystem (if it has one). On my Kobo ereader it is much much faster than the default interface and has extra bells and whistles that I really appreciate.

I manage my ebooks using a self-hosted instance of calibre-web. This allows me to sync my library to my Kobo e-reader using KOreader.

Also, turning pages is faster than with the stock reader of the device.

https://github.com/janeczku/calibre-web

I looked into building the emulator for KOReader and it requires CMake, Meson, and autotools... Why are 3 different build systems necessary?

If anyone is interested in helping Kavita, an open source self hosted reading software, finish off the Koreader Sync support, please take a look at this PR. It's 90% complete and just needs some finishing polish. The contributor got busy and hasn't returned for some time.

https://github.com/Kareadita/Kavita/pull/3311

I used this for many years on a rooted Kobo. It was great. being able to curate my own rss feeds and have them auto fetched over wifi from calibre to the e-reader, no algorithm involved, was a glimpse at how things could have been.

I use a Kobo because its overdrive integration lets me read ebooks checked out from my county library.

I'd love to give KOReader a try -- does anyone know if it can be used with library books, via overdrive or another integration? A quick search indicates KOReader doesn't work with DRM books, but I'm curious if someone has a solution.

I use it on my Kindle and I love it. I can use better and more dictionaries, the controls are ergonomic and customizable, I can easily override the font so that every ebook looks exactly the same. It supports epub and with it my Kindle is faster, the battery lasts longer and it supports dark mode on an old model while Amazon officially doesn’t. Amazing software all around!

Got this on my Kindle after the jailbreak came out in January. It's fantastic, especially the OPDB index + self hosted calibre-web means I can just download an epub on any device, drop it on a webpage, then search it on KOReader immediately. I did not want to use USB or Amazon's plumbing to transfer, so this is great. Tons of customization over the built-in reader.

Book Story on Android is a much more modern FOSS eBook reader and supports other formats too.

https://github.com/Acclorite/book-story

It says it focuses on e-ink screen integration. What are the unique challenges of e-ink screens for reading ebooks?

At least in the past, screen refresh was slower; the reflective, rather than luminescent screen changed contrast and color performance; resolution was well behind standard screens.

The first two seem easily solved; the third hard to mitigate beyond larger print and appropriate typefaces. What else?

I'm using KOReader with the PocketBook Era. The integration is top notch. Installation is simply done by copying the KOReader folder to the right directory on the device. After that you can set KOReader as the default reader, which means that you keep on using the original system software and library, but books will automatically open in KOReader.

This lets me use "Mail to PocketBook", Dropbox sync etc. or the fantastic Push-to-Kindle browser-plugin in combination with the fantastic KOReader. No flashing or jail break required.

I own a Kindle Oasis 2. Amazon stopped software updates for it so I just jailbroke it and loaded KOReader. It's way better than the official software, probably the most feature-rich and customisable document viewer I've ever seen. I regret not installing it earlier.

I gave KOReader a go after seeing this thread yesterday. I tried using it a year ago and gave up because the UI was so alien to me. It almost reminds me of Winamp in a sense.

But I gave it a go again and this time I spent time figuring out how to sync between devices. I've yet not synced files but here's what I got so far.

1. Koofr WebDAV for Reading Statistics sync 2. Kobo's built-in sync for progress

Both of these are free. This is a reminder mostly for myself that you need to use the service password for WebDAV access for koofr and not your koofr account's password. And make sure you save your koreader user credentials somewhere.

I'm still not happy with the keyboard situation, the koreader keyboard is ugly but I guess it's optimized for eink so that's something. I don't really type any notes into books. I mostly prefer being able to sync progress and have a centralized view of my reading statistics. And this works.

I copied all my books over manually for now, I'm happy with this. I have the following devices 1. Phone - OnePlus Open 2. eReader - Boox Tab Mini C 3. eReader - Boox Palma 1 4. Samsung Galaxy Tab S9 Ultra

Things I didn't know I needed: 1. The reading statistics. This tracks every eBook I read, and I don't have to use anything else. 2. Book map - Knowing how much time I spent in each chapter is a godsend. This really helps me understand things like this. 3. The speed reading module - perception expander - I'd never heard of this from Tim Ferris so it was new to me. I am giving it a go, and I'm not sure it's improving my reading speed but it feels like it's improving my comprehension!

Thank you to everyone who puts in the work on koreader!

I came across KOReader when I was trying to jailbreak my kindle. It's UI looked great on e-ink screen. And it handled almost all ebook formats properly.

Lately, I've used it on Android, and UI which is more suited for e-ink screens, look not so polished on phones, but that's just nitpicking. It's fully usable and keeps adding support for new platforms.

I like KOReader, but gave it up in favor of the default software on my Kobo Clara BW, mainly because of library navigation. I prefer to keep all my books on the device, but the only way to find them (as far as I can tell) is by author. I haven't had the time to go through my whole library to fix the author sort, and it became a real problem to find books I already possess that I want to read.

Fortunately I didn't delete KOReader, so all my setup is still there if I find a reason to go back.

When I was figuring out what reader to put in my ancient android 5 tablet (dedicated for offline ebooks) I tried KO, but the UI was way too complex. I've since been happy with Librera, but seeing all this high praise, it seems that I need to revisit KO.

Nice to see there are multiple open source readers going strong!

Shout out to the developers of KOReader. I love this application so much.

Saves me so much work in having to convert EPUB files on my Kindle. I also love how great it is at handling PDF files and cropping margins out of pages. I don't think I would ever want an e-reader that couldn't run it at this point.

It's like learning to pilot a plane.... manually. Worth learning though and reading some manuals online. Minimal margins maximizing screen real estate, gesture shortcuts for almost anything, great reflow, and so much visual customization at a default level as well as per PDF... as well as having "profiles" to switch across. It's pretty amazing.

Most major miss is more friendly syncing though. Currently only supports Dropbox (WebDAV FTP seems to have issues, even when I used OneDrive key for it which works everyone else) and doesn't actually bidirectionally sync... only downloads. Why can't there be a simple auto-sync from a specific FTP directory including reading positions and such...?!

Also doesn't support Pocket or more popular sync services (only supports Wallabag).

I'd like to try it, but I really don't want to brick my beloved Kindle Oasis second edition. It's not sold anymore, at least not in the US.

I use KOReader with Koobo Clara BW (300 ppi screen), it's great.

I still have to remove a lot of CSS from most books before uploading, but after that, it is very good, as you can fine-tune every aspect and have every book look similar. Which, in my opinion, is necessary because e-ink readers still don't have enough resolution to use all the fancy fonts authors may have thought. Also, the ability to set margins to the same is very important to me.

It’s hideous but it works great, and better that than the reverse right?

If you combine this with a Kobo you have an ereader experience without all the DRM crap.

Once you get used to it, you cannot go back! I would love for a self hosted web interface.

How does it compare to the other big foss e-book app, FBReader?

Does the focus on eink mean it's mainly aimed at jail broken eink tablets? Or aimed at phones as well?

It's certainly an incredible gem, but I do find it quite bloated in features. Which is why I plan on trying https://github.com/baskerville/plato one of these days, to see if it does everything I need.

love KOReader, recently jailbroke my kindle oasis with the new winterbreak exploit and installed it. The ability to connect via wifi to calibre is amazing.

I've installed KOReader in about 3 devices but I haven't yet cracked how to keep them all in sync - frankly, I don't know how the syncing process works.

I used to think that it syncs up both the books and the reading progress / metadata but when I tried doing it, it didn't seem to work that way. I would love to hear how folks have done this. It's about the only thing left that's keeping me from using KOReader more frequently on all my devices.

Pretty keen to try one day, a quick question for anyone who has installed it is what does it do to the battery life of the device its installed on?

is it the same, better or worse and by how much?

KOReader is the best ereader.

If I installed this ony Kindle, would it sill be able to read all the books I have with DRM? (I've bought lots of ebooks from Amazon over the years)

I am looking forward to the macOS release. I use it on my Supernote, Inkpalm 5 and my kids Kindle.

Koreader is wonky in places. But, like vi and bash, you get used to the wonkiness and it works well enough for the job and is everywhere.

My Kindle got hardly any use nowadays thanks to this gem.

Out of the box it's a bit hard to use. Love it after configuring intuitive gestures for navigation.

Especially love the frontlight switch that lets me read while helping my kid fall asleep.

Good points, especially about the implementation details.