[Update] 2026-07-27 - Library performance, storage templates

[Erlend]

This update brings huge performance improvements to everything related to handling your library, including file operations, downloads, synchronization, and browsing. It also adds a new storage template system, which lets you decide how your books are stored, and some smaller usability improvements.

• Implemented storage templates, which lets you decide how your files are stored (for example in a folder per author, or a folder per series).
• Improved customization of which info to show on books in the library, using the same template system as the storage templates.
• Greatly improved performance when loading huge libraries from Calibre content servers, cloud providers, the local library, and external folders.
• Added a 'Part of series' filter to the library filter system.
• Added custom sorts, which can be created by combining multiple of the base sorts.
• Improved performance and feedback when running a book source synchronization.
• Book source synchronization can now be minimized and continue working in the background.
• Now stores passwords and tokens for book source and data synchronization connections securely.
• Fixed parsing of MOBI files without internal compression.
• Fixed 'Open in' action not working correctly when books were stored on external storage.
• Fixed some controls (most notably the selected radio button in a list) being invisible due to wrong theme colors being set in native Android.
• Merged the dictionary/AI lookup into the text selection popup to make it easier to use.
• If a selected word has a stored dictionary/AI lookup, it will now be shown immediately in the text selection popup.
• When adding new Calibre book sources, you can now choose to copy the username and password from an existing connection instead of having to enter it again.

[milady133]

Those storage templates will come handy, I'll test again your app with that implemented.

I've tested it some months ago on my Hisense eink phone (used as a commuting reader) running an Android version old enough to work more or less with the old Calibre Companion app and Bookari as a reading app (both discontinued).

Your app seems to be able fill gaps in other apps, but when I tested back then, I realized the book library on the phone would be a problem with the lack of organization, all the books downloaded to the default folder. For those of us who like to carry all our ebooks on the device, after downloading a couple of hundreds to a unique folder with more ebooks.

[Erlend]

Great! Please let me know if you try it, and find any issues or have any improvement suggestions! Or even just if it works perfectly, that's also nice to hear.

The new library system should work well regardless of library size. Well, to a limit, of course -- it’s been tested with a library of 100 000 books. The first load/download will take a little while, but after that it should be very fast.

[milady133]

I'm trying it on my eink phone, and it's working quite well.

Because I had tried it before, when I changed the default location of books it had some issues moving part of the already existing on the device to a new location. I had to delete those books because it couldn't match them to books in Calibre next time I connected. Although that might be because I think I also mixed the connection mode, I've tried before both connecting to Calibre as a wireless device and connecting to the content server, and I think the books downloaded when connecting as wireless device couldn't be moved, the template I use in Calibre to name the downloaded file wasn't to JetReader liking 😀.

Anyway, I finally settled to connecting to Calibre Content Server, and after some adjustments I was able to download all my TBR books and books I frequently re-read.

One thing I liked is that when connecting to Calibre Content Server you have the option to configure to which library you want to connect. With Calibre Sync you connect and sync to all the libraries at once, you can't choose. I have some experimental libraries with duplicated books, and a temp library where books pending to validate before moving them to the final library and not so interested in having those libraries in the device.

By the way, I don't need it, but other people might find useful to be able to add the library name to the path of the books downloaded, or if they're using virtual libraries or a custom column in Calibre use that in the template to determine the path, I don't know if that would be possible, or given that other people don't use Calibre connections to download books it would be incompatible with those other connections.

Now the reader part of the application. I'm not much picky about formatting, so I'm not your test user for that, but I think that part other users might find that it needs improvement. I'm currently reading Doomsday Book, from Connie Willis, and when I read in my Kobo there are parts in the chapters where the size of the letters is smaller to mark that is an annotation in the book, apart from the main narration, and I don't notice that change in size in my phone. That might be because is a phone, with a smaller screen size, but it could be because JetReader overrides the size formatting.

Another thing I've noticed is that when you call up the menu when reading (in my case I do it to navigate to another chapter) sometimes the lower part of the screen reserves the space for the menu when returning to reading again, maybe it's the space for the controls when using text to speech, but I'm not using it, I only see the blank space. It is not something happening every time I call up the menu, I can't reproduce it at will, if I find a pattern for this behavior I'll report here.

[Erlend]

Thank you for the very thorough reply! Very good to hear that it generally works well, even though there are some things that should be improved.

Originally Posted by milady133

Because I had tried it before, when I changed the default location of books it had some issues moving part of the already existing on the device to a new location. I had to delete those books because it couldn't match them to books in Calibre next time I connected. Although that might be because I think I also mixed the connection mode, I've tried before both connecting to Calibre as a wireless device and connecting to the content server, and I think the books downloaded when connecting as wireless device couldn't be moved, the template I use in Calibre to name the downloaded file wasn't to JetReader liking 😀.

I tried making the new library location system backwards compatible, but it's probably not perfect. Your solution of simply restarting the library is a good workaround when issues arise. Could be some edge case when you mixed different connections in a previous version. I'll keep it in mind, and see what I can improve in the future!

Originally Posted by milady133

By the way, I don't need it, but other people might find useful to be able to add the library name to the path of the books downloaded, or if they're using virtual libraries or a custom column in Calibre use that in the template to determine the path, I don't know if that would be possible, or given that other people don't use Calibre connections to download books it would be incompatible with those other connections.

The library name is already possible, using the {source_name} template item -- as long as you haven't renamed the source to something else, it will default to the library name. Virtual libraries or custom columns I hadn't considered. I'll add that to my list.

Originally Posted by milady133

I'm currently reading Doomsday Book, from Connie Willis, and when I read in my Kobo there are parts in the chapters where the size of the letters is smaller to mark that is an annotation in the book, apart from the main narration, and I don't notice that change in size in my phone.

I'll have a look at this. When picking font size in JetReader, there is a "Forced" checkbox. If this is checked, then it will override all font sizes in the book (meant to help with old/badly formatted books). If that's unchecked, however, JetReader should be able to show different font sizes like other readers.

Originally Posted by milady133

Another thing I've noticed is that when you call up the menu when reading (in my case I do it to navigate to another chapter) sometimes the lower part of the screen reserves the space for the menu when returning to reading again, maybe it's the space for the controls when using text to speech, but I'm not using it, I only see the blank space. It is not something happening every time I call up the menu, I can't reproduce it at will, if I find a pattern for this behavior I'll report here.

Hm, yeah, that sounds like a bug. I did fix something similar while working on the soon-to-be-released update, so it might be fixed, but I can't guarantee it. If you continue to experience it after updating, and/or find a pattern, please let me know!

[milady133]

Originally Posted by Erlend

I'll have a look at this. When picking font size in JetReader, there is a "Forced" checkbox. If this is checked, then it will override all font sizes in the book (meant to help with old/badly formatted books). If that's unchecked, however, JetReader should be able to show different font sizes like other readers.

I'll have a look at that option, I don't remember adjusting it, so it might be checked.

Something I forgot to mention, the translation to Spanish is quite warped 😅. A lot of texts seem to be Italian, and you must have run a find&replace for a couple of 3 letter words resulting in a lot of replacements in the middle of other words. Do you use some translation web system so I can take a look and correct some texts?

[Erlend]

Oh shoot. I think you're right, I must have mixed in the Italian language file at some point. I just ran a full new re-translation, and although I don't speak neither Italian nor Spanish, I can see that some strings that looked Italian now looks more Spanish. But I have no idea if it's correct.

I'm using a system called Weblate. If you would take a look, I'd be very grateful! It's a bit messy on the first registration, so make sure you re-visit this exact link after registering a user:
https://weblate.erlenddahl.no/projects/jetreader/
(I haven't actually tested it with external users yet, so please let me know if you hit any problems.)

Note that the strings in your app may not correspond fully to the strings in Weblate, since I ran a full re-translation, and I've also added some new strings while working on a new update. Might be easier for you to wait for the update, and then if/when you spot anything weird, you can go into Weblate and search for the weird strings.

[milady133]

OK, I'll take a look when I have some time. I'll probably wait for the update