I'm looking for an ebook reader application that:

  • Is open source
  • Supports opening books without adding them to a 'library' (and is not very slow when working that way)
  • Does not use node.js (so no electron, etc.)
  • Supports epub and .mobi

I don't want a library because I don't like that UI much (I'd rather open books from the command line), and I don't want to have to deal with the resulting state (neither in the application itself nor on my disk, unless it's super obvious it's just cache state that can be safely deleted). If it's fast enough I guess I'd be OK with writing a wrapper script to delete the directory used by the application after each run, though I guess that would lose last-read positions.

I don't want node.js because I prefer not to have the sort of dependencies that come with that.

  • 1
    I guess you've already tried Calibre (yes, it has a library – but no, it's not mandatory; you can open books from the command line, and it supports epub, mobi and more) – and it was "too slow"?
    – Izzy
    Jun 29, 2020 at 7:22
  • Calibre does have the features whose presence I don't want, for the reasons I try to explain in the question (search for "because"). Maybe my explanation is unclear? Jun 30, 2020 at 20:42
  • Well, in a way. If you open an eBook from the command line, Calibre directly opens its eBook reader. You won't see the library at all then, so its UI shouldn't matter in that case. I have no idea what you mean by "resulting state" (again, in this workflow the library isn't touched at all – that's the way I use Calibre for about 10 years now with thousands of books meanwhile). And it's not using NodeJS (or I wouldn't have installed it in the first place either). I'm using Calibre mainly for eBook creation/conversion from CLI, and the reader to check results.
    – Izzy
    Jul 1, 2020 at 9:34
  • 1
    I also use Calibre that way, and that's why I posted this question. By state, I mean I'd rather not have books there that look like they might be something I don't have elsewhere. Of course I could organize my files better to keep books in one place, but that's a work in progress for me right now -- in fact that work in progress is what prompted me to post this question. Plus I'd just prefer a UI that doesn't even have a library UI at all. Jul 2, 2020 at 19:03
  • 1
    I take it back: ebook-viewer does not add books to the library. In the past I've run the calibre program instead of the ebook-viewer program (both from bash), and the former does add the book specified as argument to the calibre library. I recall reading something on the web -- from the author I think -- that seemed quite clear that they actively wanted never to support a command line entry point like ebook-viewer, but apparently that was not what was intended. Aug 22, 2020 at 21:56

2 Answers 2



  1. If you already have the calibre package installed but don't want to add it to calibre's library, you can use the included ebook-viewer application from that package to avoid calibre's library nonsense. For example, under Mint 19.3 Cinnamon, I have the nemo file manager and all I did was right-click > Open With > other application > ebook-viewer > add to list. It then shows up in the Open With menu and I can simply view the epub/mobi/etc directly without loading up the full calibre application or dealing with any library scanning/etc. It seems to open pretty quickly. If you are having trouble finding it in the menu, the full path should be /usr/bin/ebook-viewer on most Ubuntu-based distros.

Other options

  1. Okular is another viewer that can open epub/mobi without adding to a library. Like calibre, it is available from the central repositories for many popular distros.

  2. BookWorm [1]

  3. Foliate [1]

  4. Easy eBook Viewer [2]

  5. GNOME Books [2]

  6. Lucidor [3]

  7. epr - cli-based python3 epub reader. no mobi support AFAIK.

  8. Firefox has an EPUBReader addon and a MOBI Reader addon. Please note I have not tried either of these personally but since FF addons are just javascript, you should be able to view the source whether the authors link to it or not (I did not check). In theory, you should still be able to launch from terminal using file uris, e.g. firefox -private-window -url "file:///path/to/your/file.mobi"


  1. opensource.com
  2. omgubuntu.co.uk
  3. itsfoss.com
  • 1
    if you split out an answer that says "calibre using ebook-viewer" I'd be happy to mark it accepted Aug 22, 2020 at 21:58
  • @Croad Langshan - it seems that SE prefers me to edit existing answers so I have restructured my original answer to more specifically apply to the situation in your original post while still providing alternatives for anyone else coming in from search engines.
    – zpangwin
    Aug 24, 2020 at 18:11

FBReader - C++/Qt application. Very fast e-book reader, supports ePub, fb2, mobi and other formats.

It does have a library button -- all books that you have opened will be added there -- but it is more like "Recently opened files" thing. It is not affecting speed and you could open files directly (without importing them first) so you may even not notice that there is a library feature.

  • It seems FBReader hasn't seen development in some years, and when trying to compile it I ran into a library that's deprecated. Aug 27, 2020 at 18:55
  • @CroadLangshan Yes, Linux version wasn't updated since 0.99.4, but it is still works perfectly for epub and fb2 (at least from my experience). I haven't tried to compile it myself because it's already in almost all distributions: repology.org/project/fbreader/information
    – anlar
    Aug 27, 2020 at 19:18
  • I'm sure I could compile it, but I'm not keen to use an application that's not maintained, especially not a C/C++ one that depends on unmaintained libraries (because no security attention, presumably). Aug 27, 2020 at 19:48

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