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.
With eInk screens it's an interesting story. Because when your page is shown, there is no need for CPU at all for keeping it, so in an ideal world for such devices every page flip is a micro-cycle of waking up from the deep sleep, doing a job and going back to sleep. With such a lifecycle it's even better to measure the battery life not in hours but in page flips. When KOReader supports going to the deep sleep between flips then the difference between it and the bundled software should be small. But if for some reason there's no going to DS between flips, the battery life will drop significantly and back to time units per charge.
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.
How do you connect your Kindle to the internet to access OPDB/Calibre-web without losing your jailbreak?
Every time I connect my Kindle 4 to the internet, it disables developer mode and I have to rejailbreak. This is despite using an update disabler plugin (I've tested them all).
It probably depends on your model, I jailbroke my paperwhite 7 (10-year old model) back in January, and it hasn't been reverted since, even though it's always connected to the internet.
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.
> 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
That's insane, I thought it was already good with a whole page, I will have to explore this more. Might need to update it as well, since I installed it a few years ago.
Have they really improved the interface? I tried it a few years ago and while it certainly has a lot of features I found it be sort of confusing to use compared to the built-in Kobo, Kindle, Boox options.
Some of those features like the column panning are also available in Boox's default reader.
In my opinion, yes. On the other hand, I have been using KOReader for many years. When I started using it, it was very rough. At one point there was a fairly significant overhaul. Since then, there have been smaller incremental changes (which amount to a lot across the years). Of course, opinions of user interfaces will vary.
I am not going to claim that it is perfect. They cram a lot of functionality in there that serves a very diverse audience. The volume of options is going to have a negative impact is going to have a negative impact for anyone wanting a simple, to-the-point interface. The diverse audience bit means that virtually noone is going to be interested in a majority of the features, even though I suspect that a majority of users will interested in a combination of features that they won't find in other products.
While I may have been a bit unfair in saying that most commerical reading software is geared towards selling novels, I don't think that assessment is too far off base. Most software does appear to be designed for people who just read novels. KOReader is geared towards people who care about features that other reading software rarely provides.
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.
I ended up getting a faster Kobo! Thankfully, the slow load is a one time thing, per book. Depending upon when you tried it, KOReader has switched to a progressive model of updating it's caching (with most of it being handled in the background) when modifying a book's formatting.
That said, I think this may be mostly based upon a book's formatting. Messing around with upload options in Calibre may help. (For example, Calibre recently added an option to speed up load times with Kobo's reader software.)
That Calibre option isn't relevant -- it's for Kobo's native stuff, which treats "KEPUB" different from regular ePub, in ways that I haven't bothered to remember.
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.
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.
It really shines on e-ink Android readers such as the tablets Boox makes. I almost exclusively use it on my Boox because the built-in reading app is terrible.
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.
Koreader doesn't integrate with overdrive, but it's trivially easy to install it on your Kobo alongside the Kobo OS. You can continue to use overdrive on your Kobo and also dip into koreader for the better PDF viewer etc.
I tried koreader on a kobo. I wouldn't call it trivially easy when I installed it last year, and I promptly uninstalled it and removed all the hacks so I could get back to a sane installation of the Kobo OS again.
I think maybe for a kindle it might be worth it, but the reality is for Kobo, it's probably more hassle than it's worth.
I found my time better spent setting up a calibre-web in a docker container and then having my kobo sync to that. And that was awesome.
I don't remember frankly, maybe something with the script, maybe something with KFMon. Lack of integration with the Kobo OS itself? Maybe it had to be rooted to install KFMon, but I was reading Koreader could just run inside nickel menu maybe? But yet the script installed KFMon?
Again, I don't remember. And whatever it was it's not worth me trying to reinstall it just to remember what it was, and then to uninstall it again.
The installation instructions are a bit windy, so many people miss that there's a simple script that automates the install for you.
The one thing you have to watch out for : You need to return those scripts whenever Kobo has an update. You won't lose your data or anything but a standard Kobo update dialed disables Koreader
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?
How long was it since you saw an e-ink screen the last time? Resolution has been excellent for a while now. Refresh is still slow, but that doesn't matter for reading books. Contrast is fine, but not comparable to other display types.
Depends on device, but retina quality I would say. You cannot see individual dots so text appears like high quality print. The example screenshots are high resolution, you have to click them.
I think you're right about the screenshot resolution.
Something is wrong with the layout that makes it awkward for me to read. The word spacing, at least, seems awful. Look at the lines "meaning behind printed words ..." (near top) and "widely believed that ..." (near bottom) compared to the lines above and below them.
Maybe it's the full justification adjustment - the text in the box is much better. Even the dictionary popover has word spacing problems.
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:
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
Same experience on a PaperWhite 2, been using it for a long time.
It is a good reason to look into rooting, PDF reflow and the function to remove margins make it possible (at least tolerable) to read PDFs when an .epub / .mobi is not available.
You can also run Alpine Linux on a rooted Kindle with graphical interface, I found it amazing but ultimately not that useful with the limited system memory.
PDF reflow is one of the major reasons I am using Koreader. The whole thing is very clever and works extremely fast given the limited nature of these devices.
The best solution I have found is to buy a DRM book, then download the DRM-free version from libgen. That may not be what you're looking for but it keeps me in Calibre.
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.
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.
I believe Calibre (very) recently added a feature to make conversion to kepub automatic when transferring to a Kobo, so things may have changed on the ease of use front.
OPDS (Open Publication Distribution System) is protocol in the background. Jellyfin has a plugin for OPDS and works by simply dropping a file in specified directory, but it doesn't support multiple catalogues (i.e. one per library/directory).
Protocol is atom based, chatgpt was able to make a custom OPDS server for my needs within minutes, it took another hour or two to fix and customize generated code.
I've used CoolReader in the past, and recently suggested its sucesslr LxReader[0] to my partner, while I like the simplicity in MuPdf[1]. What do you think are the biggest advantages of Book Story? I might give it a try.
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.
The progress sync is separate from how books get onto the various devices (at least as far as I know). Something OPDS capable works well to get the actual files across a network (or calibre via usb). For progress you can use their provided sync server or run your own (the original one gave me enough trouble to write my own implementation).
It includes a bunch of dependencies as submodules and builds those as well. I haven't verified that's the reason, but I'm willing to bet a decent amount of money it is.
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.
113 comments
[ 2.7 ms ] story [ 124 ms ] threadKoreader 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.
is it the same, better or worse and by how much?
Every time I connect my Kindle 4 to the internet, it disables developer mode and I have to rejailbreak. This is despite using an update disabler plugin (I've tested them all).
[0]: https://kindlemodding.org/jailbreaking/WinterBreak/
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.
That's insane, I thought it was already good with a whole page, I will have to explore this more. Might need to update it as well, since I installed it a few years ago.
Some of those features like the column panning are also available in Boox's default reader.
I am not going to claim that it is perfect. They cram a lot of functionality in there that serves a very diverse audience. The volume of options is going to have a negative impact is going to have a negative impact for anyone wanting a simple, to-the-point interface. The diverse audience bit means that virtually noone is going to be interested in a majority of the features, even though I suspect that a majority of users will interested in a combination of features that they won't find in other products.
While I may have been a bit unfair in saying that most commerical reading software is geared towards selling novels, I don't think that assessment is too far off base. Most software does appear to be designed for people who just read novels. KOReader is geared towards people who care about features that other reading software rarely provides.
Conversely, the built-in software never struggled with that file.
That said, I think this may be mostly based upon a book's formatting. Messing around with upload options in Calibre may help. (For example, Calibre recently added an option to speed up load times with Kobo's reader software.)
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.
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'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 think maybe for a kindle it might be worth it, but the reality is for Kobo, it's probably more hassle than it's worth.
I found my time better spent setting up a calibre-web in a docker container and then having my kobo sync to that. And that was awesome.
The Kobo OS is good enough for me to recommend it to family, there's nothing wrong with the iPod experience of uploading books.
But Koreader+Tailscale+Kavita OPDS is the best reading experience I've ever had.
Again, I don't remember. And whatever it was it's not worth me trying to reinstall it just to remember what it was, and then to uninstall it again.
The one thing you have to watch out for : You need to return those scripts whenever Kobo has an update. You won't lose your data or anything but a standard Kobo update dialed disables Koreader
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?
Something is wrong with the layout that makes it awkward for me to read. The word spacing, at least, seems awful. Look at the lines "meaning behind printed words ..." (near top) and "widely believed that ..." (near bottom) compared to the lines above and below them.
Maybe it's the full justification adjustment - the text in the box is much better. Even the dictionary popover has word spacing problems.
That's a big deal for reading long-form.
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
It is a good reason to look into rooting, PDF reflow and the function to remove margins make it possible (at least tolerable) to read PDFs when an .epub / .mobi is not available.
You can also run Alpine Linux on a rooted Kindle with graphical interface, I found it amazing but ultimately not that useful with the limited system memory.
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.
https://news.ycombinator.com/item?id=32442549 has some more tips.
Oh and https://bookshop.org/beta-search now actually lets you check "DRM-free" when you search, which is a very good step in the right direction!
I have a dream of https://news.ycombinator.com/user?id=marginalia_nu taking up the mantle. Though I think anyone could make something that's better than what we have now, which is nothing.
[0]: https://www.reddit.com/r/Calibre/comments/1c2ryfz/2024_guide...
[1]: https://www.mobileread.com/forums/showthread.php?t=361503
[2]: https://forum.linuxconfig.org/t/calibre-and-dedrm-problems/8...
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.
https://pgaskin.net/kepubify/
Also, turning pages is faster than with the stock reader of the device.
https://github.com/janeczku/calibre-web
Protocol is atom based, chatgpt was able to make a custom OPDS server for my needs within minutes, it took another hour or two to fix and customize generated code.
I think it works using the file name of the epub. Not sure.
https://github.com/Acclorite/book-story
[0] https://gitlab.com/coolreader-ng/lxreader
[1] https://f-droid.org/en/packages/com.artifex.mupdf.viewer.app...
The UI is so good, from quick look on LxReader's play store page, the UI is a bit basic.
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.
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.