[HN Gopher] KOReader: Open-Source eBook Reader
___________________________________________________________________
KOReader: Open-Source eBook Reader
Author : charleshan
Score : 375 points
Date : 2025-03-31 19:52 UTC (1 days ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| philips wrote:
| 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.
| totetsu wrote:
| 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.
| boznz wrote:
| 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?
| philips wrote:
| What device? I haven't noticed an issue on android devices. On
| my rooted kindle it is a bit less battery but I haven't
| measured it.
| complexworld wrote:
| On my Kobo Libra 2 I never noticed a difference.
| herboh wrote:
| I installed on a brand new kindle and didn't notice any
| difference.
| Agraillo wrote:
| 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.
| dantondwa wrote:
| On my Paperwhite from 2018, the battery life is better on
| KOReader than on Amazon's firmware.
| sodality2 wrote:
| 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.
| pidgeon_lover wrote:
| 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).
| homebrewer wrote:
| 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.
| rraghur wrote:
| Kual+ had an option to stop auto updates... KT4 here
| sodality2 wrote:
| I used Winterbreak [0] and used the renameotabin extension to
| block updates.
|
| [0]: https://kindlemodding.org/jailbreaking/WinterBreak/
| andro_dev wrote:
| KOReader is the best ereader.
| _emacsomancer_ wrote:
| And it works on Android too. Even for devices that aren't
| e-ink, I prefer KOReader to anything else.
| Multicomp wrote:
| I prefer Moon Plus Reader because it does not force itself to
| be full screen.
| II2II wrote:
| 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.
| exe34 wrote:
| > 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.
| graemep wrote:
| It was the only thing I could find that works well on a Linux
| tablet. Other readers have poor controls for a touch screen.
| goosedragons wrote:
| 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.
| E39M5S62 wrote:
| 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.
| II2II wrote:
| 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.)
| mkozlows wrote:
| 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.
| homebrewer wrote:
| I think it builds a full text search index by default, have you
| tried disabling that?
| SheinH wrote:
| 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.
| locusofself wrote:
| 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.
| beAroundHere wrote:
| 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.
| lucius_verus wrote:
| 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.
| jtmoulia wrote:
| 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.
| lucius_verus wrote:
| 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.
| bb88 wrote:
| 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.
| cyberpunk wrote:
| It's two .tgz files extracted to / ... how is that not
| trivially easy?
| Larrikin wrote:
| What's the issue you had? When you reboot or quit you're
| kicked back to regular Kobo and you open up Koreader
| through a menu option.
|
| 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.
| bb88 wrote:
| 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.
| BeetleB wrote:
| 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
| mmooss wrote:
| 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?
| jhot wrote:
| I think the eink focus is mainly in the UI as it avoids
| scrolling in favor of pages and tabs.
| carlosjobim wrote:
| 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.
| mmooss wrote:
| How high is resolution? The example screenshots look pretty
| low.
| carlosjobim wrote:
| 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.
| mmooss wrote:
| 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.
|
| That's a big deal for reading long-form.
| OuterVale wrote:
| 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
| jwrallie wrote:
| 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.
| ValtteriL wrote:
| 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.
| fisian wrote:
| Can anyone recommend a site for buying DRM free books so I can
| read it with KOReader?
| BHSPitMonkey wrote:
| I've purchased a lot of mine from Kobo. There's also Standard
| Ebooks if you want free, high-quality reproductions of public
| domain works.
| internet_points wrote:
| Note that with Kobo you need to check. I bought one there
| once thinking it was DRM-free, it was not.
| wahnfrieden wrote:
| anyone know the answer for japanese language books?
| theshrike79 wrote:
| Not for buying, but for free: https://standardebooks.org
| internet_points wrote:
| https://www.libreture.com/bookshops/ has a list of stores (and
| for Norwegian books there is https://ebok.no/ ), but I have
| found no way to search "globally" (across sites like that) for
| DRM-free ebooks.
|
| 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.
| troyvit wrote:
| 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.
| _emacsomancer_ wrote:
| One can also remove DRM from books one purchased with
| Calibre+DeDRM plugin.[0],[1],[2]
|
| [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...
| vlowrian wrote:
| For books in German, Beam is a very good choice:
| https://www.beam-shop.de/
| arkx wrote:
| 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.
| deng wrote:
| 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.
| BeetleB wrote:
| 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.
| theshrike79 wrote:
| This can also be fixed by converting books to KEPUB with
| Calibre, it'll also (for some reason) make page turns faster.
| lazyeye wrote:
| I find it easier to do this using kepubify in a script
|
| https://pgaskin.net/kepubify/
| freeAgent wrote:
| 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.
| BeetleB wrote:
| Yes, that's true, but I'd rather keep them as ePub so it will
| work well with other readers.
| sangpugogogo wrote:
| Good points, especially about the implementation details.
| ZeWaren wrote:
| 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
| stanac wrote:
| 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.
| bobchadwick wrote:
| Are you able to sync progress? I can access my calibre-web
| library, but I've been unable to figure out how to sync
| progress.
| ementally wrote:
| Book Story on Android is a much more modern FOSS eBook reader and
| supports other formats too.
|
| https://github.com/Acclorite/book-story
| ajot wrote:
| 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.
|
| [0] https://gitlab.com/coolreader-ng/lxreader
|
| [1]
| https://f-droid.org/en/packages/com.artifex.mupdf.viewer.app...
| stuxnet79 wrote:
| 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.
| thallian wrote:
| 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).
| throwaway2046 wrote:
| I looked into building the emulator for KOReader and it requires
| CMake, Meson, _and_ autotools... Why are 3 different build
| systems necessary?
| arp242 wrote:
| 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.
| Ciantic wrote:
| 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.
| Mossy9 wrote:
| 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!
| coolca wrote:
| Once you get used to it, you cannot go back! I would love for a
| self hosted web interface.
| GordonS wrote:
| 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)
| kristofferR wrote:
| Yeah. You need to remove the DRM first ofc, but thats really
| easy: https://www.youtube.com/watch?v=5CIFbUIKwDY?t=219
| no_time wrote:
| 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...
| jszymborski wrote:
| Running on my Pixel 6a, I wouldn't really characterize it as
| super responsive. This context, I think, helps me understand
| why.
| mdhen wrote:
| 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.
| corank wrote:
| 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.
| dantondwa wrote:
| 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!
| a-french-anon wrote:
| 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.
| dfxm12 wrote:
| Is it not easy enough to just ignore the features you don't
| need?
| a-french-anon wrote:
| Those mean a pretty cluttered UI, in my eyes.
| Gormo wrote:
| And what's wrong with a UI being "cluttered", especially if
| the alternative is that it fails to expose the software's
| full functionality?
| AdmiralAsshat wrote:
| 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.
| ksynwa wrote:
| 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.
| user3939382 wrote:
| 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.
| vlowrian wrote:
| 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.
| codybontecou wrote:
| How are you getting the Push-to-Kindle plugin to sync to
| KOReader?
| rat87 wrote:
| 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?
| presbyterian wrote:
| You don't need to jailbreak, there are many eink tablets that
| will run it via sideloading (Kobos, for example, and I believe
| Nooks as well) and eink Android devices (like the BOOX line)
| that can just install it from F-Droid
| majora2007 wrote:
| 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
| themadturk wrote:
| 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.
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(page generated 2025-04-01 23:01 UTC)