New Reading App with Calibre Sync – Looking for Testers

[Erlend]

Hi there!

A few years ago, I was looking for a reading app that could track the kind of stats I care about, and also integrate well with Calibre. I didn't find quite what I wanted, so I started building my own. It's called JetReader.

JetReader is aimed at readers who:

• Like seeing their reading stats
• Want to sync their device library with Calibre
• Read on multiple devices and want their progress and data kept in sync

Syncing works through Dropbox, WebDAV, or a free JetReader account. It is also possible to use JetReader only to synchronize books with Calibre, and open the books in another app.

I've been using the app myself for about three years, gradually improving it and adding things I found useful. In addition to the core features mentioned above, I've also added a simple web page to view and share reading stats, and an AI-based tool that explains words or phrases in the context of the book, which has been really helpful when I'm reading in other languages than my mother tongue (which is mostly all the time).

The app supports common formats like epub, mobi, azw, fb2, txt, and html. It's currently Android-only, but it's built with a cross-platform framework, so iOS support is possible if enough people are interested.

At this point, JetReader does most of what I need it to. I'm now looking to hear what others might want from it. If this sounds like something you'd use, I'd really appreciate your help testing it and hearing your thoughts.

If you think this sounds interesting, you can ...

• find some more information on the web page,
• download the beta version of the app from Google Play,
• see an example of the shareable statistics page
• see a basic roadmap (which is very open for suggestions)

For some silly reason, it is impossible make the test version of the app free on Google Play, so here's a list of promo codes you can use to redeem the app for free. Please only use a single one, and if you let me know which one, I'll cross it out.

1. (used)
2. (used)
3. 3DSHRBLKVDAAL716GCUFXNK
4. NE04HYRXFGLMAVJFUS5PUJV
5. 1E92MMHSVL66GP5XUM93WCA
6. EV76F7R7XPE5QRA5Z9ZHK95
7. 2D41MZBK4P95APBRP4PJ01Q
8. 1CH09WF3RD66EM0G820E34B
9. YQNY6BNGZZ8G4393P81G6W7
10. E3SY9DY046G1YNZVHXDBNJC

To redeem a code, open the Google Play Store app, tap the Profile icon at the top right, tap Payments & subscriptions and then Redeem code.

(If all are used, you can send me a DM here at the forum or an e-mail to erlend.dahl@gmail.com, and I'll send you one.)

--
Erlend

[nqk]

I have just given ít a try, but it can't load my content server. self-signed certificate issue maybe?

Sent from my Pixel 7 Pro using Tapatalk

[Erlend]

Thank you very much for trying it!

Hm, that could be! I haven't tried using self-signed certificates myself, but I'll take a look at it right away.

Is there an option in Calibre for adding certificates that I have overlooked, or are you behind a reverse proxy or something?

Edit: Yeah, I found it. Working on a fix!

[Erlend]

I've uploaded an update to the app now (version 2025-04-12b), which adds a checkbox in the Calibre connection configuration that let's you ignore invalid (or self-signed) certificates when connecting to a content server (quick explanation here).

[nqk]

Originally Posted by Erlend

I've uploaded an update to the app now (version 2025-04-12b), which adds a checkbox in the Calibre connection configuration that let's you ignore invalid (or self-signed) certificates when connecting to a content server (quick explanation here).

The connection to calibre content server works fine, I could download the epubs, but JetReader doesn't open any.

Error: Failed to open this book: Index was outside the bounds of the array.

[Erlend]

Oh no, that's weird. Would you mind trying a few files in quick succession, then sending me a log file? You can find the log files in Settings => About => Show log file, then you can for example tap "Share", and send it to yourself in an e-mail or something, then upload it here (or send it directly to my e-mail if you wish, erlend.dahl@gmail.com). Hopefully the .error.txt file from today contains what I need, but you could also send the .debug.txt file if you want. There shouldn't be any personal information in any of them, but there could be filenames and titles from your books.

Sorry about that, and thank you so much for your patience so far!

[nqk]

Error log sent via email.

Sent from my Pixel 7 Pro using Tapatalk

[Erlend]

Thank you! Looks like there are some issues with the encodings in these files (probably due to the language). I'm working on a fix!

[JSWolf]

If you make a proper version for iOS, I'd be happy to test your app.

[Erlend]

Originally Posted by nqk

The connection to calibre content server works fine, I could download the epubs, but JetReader doesn't open any.

Error: Failed to open this book: Index was outside the bounds of the array.

This is now fixed in version 2025-04-13 that was just made ready on Google Play. It was an issue with certain symbols I haven't seen before messing up the table of contents. Hope everything works properly now!

Originally Posted by JSWolf

If you make a proper version for iOS, I'd be happy to test your app.

Thank you! Once the Android version has stabilized, I'll try to build it for iOS as well. From experience, I know there's usually a lot of adjustments (mostly in the user interface) that has to be done for new platforms, but I hope it's not too much.

[kiwibelgian]

Okay, initial feedback.

I've used code no. 2 so you can remove that.

On my boox page reader the underlying android notification icons are still visible/active at the top of the screen and are overlaid by the app top level items so selecting the app icons is difficult.

When adding books already on the device the only option appears to be to select files. My books are stored under author/series/file folder structure so an option to select a folder and add all books from that folder plus subfolders to the library would be useful.

Also, for local books are you just storing metadata or are you making a copy of the book ?

Connecting to my calibre content server the auto detect feature failed to find the instance though adding it manually worked okay.

I could not see anywhere to specify where to save downloaded books

When connecting to calibre I get the "sort order" window. If I select for example "series" all I see is a list of books - not a list of series which I can drill down into to find the books in a series, ditto for tags, genre etc.

My library has a large number of books so if sorting by title for example a means of moving around the list of books would help - maybe a clickable ABC...Z selection to quickly jump to books starting with the clicked letter.

Also a search option would be useful.

[Erlend]

Thanks!

About the underlying Android notification icons: does this happen on the Home screen, on the Reader screen (when you're inside a book), or both? I just pushed an update (2025-04-14) that has a "Report a problem" button in Settings => About. Would you mind clicking this button, and just typing something quick about the icons being visible, then submitting it? That would send me a set of technical parameters about your screen and Android configuration, that could help me debug this issue. (I've seen the same on my Onyx Boox device previously, but I thought I had solved it. Obviously not.)

If you could also force an auto detect attempt (for example Settings => Calibre => Automatic server connection => Test connection), and report that as a separate problem right after the auto detection failed (then it will be in the short log excerpt that is included in the problem report), that would also be very useful!

Adding books: yes, in the current version, you can only select files (one or more in the same folder), or add books by connecting to a Calibre content server. The app stores a copy of the book files in its internal data folder, and this is also why you cannot specify where they are saved -- they are always saved internally. I have on my todo list to make this more customizable, and for example allow adding all books in a folder. That side of things (adding books) is not a lot of work, I think. But the other side (storing books outside of the app data folder) is a bit more complicated. For that to work in your use case, you would have to a) set the storage location to your folder, and b) tell JetReader how to create the same folder structure (author/series/file, probably also with a pattern in the file name, like [series index] - [title], or something). Does that sound like a good solution, or do you have other suggestions?

And yes, the Calibre browser is a bit simple, as it is based on the fairly simple content server API. So the "sort order" window is just that: it sends a sort order to Calibre, telling it in which order to list the books. But nothing is impossible; it's just a few more calls to download enough data to make a better categorization on the client side, allowing you to drill down, and even search (like you can in the "real" library browser for books that are already added to your JetReader library). I'll add this to my todo list!

[kiwibelgian]

Originally Posted by Erlend

About the underlying Android notification icons: does this happen on the Home screen, on the Reader screen (when you're inside a book), or both? I just pushed an update (2025-04-14) that has a "Report a problem" button in Settings => About. Would you mind clicking this button, and just typing something quick about the icons being visible, then submitting it? That would send me a set of technical parameters about your screen and Android configuration, that could help me debug this issue. (I've seen the same on my Onyx Boox device previously, but I thought I had solved it. Obviously not.)

It's only happening on the home screen. I've sent the report.

Originally Posted by Erlend

If you could also force an auto detect attempt (for example Settings => Calibre => Automatic server connection => Test connection), and report that as a separate problem right after the auto detection failed (then it will be in the short log excerpt that is included in the problem report), that would also be very useful!

Report sent.

Originally Posted by Erlend

Adding books: yes, in the current version, you can only select files (one or more in the same folder), or add books by connecting to a Calibre content server. The app stores a copy of the book files in its internal data folder, and this is also why you cannot specify where they are saved -- they are always saved internally. I have on my todo list to make this more customizable, and for example allow adding all books in a folder. That side of things (adding books) is not a lot of work, I think. But the other side (storing books outside of the app data folder) is a bit more complicated. For that to work in your use case, you would have to a) set the storage location to your folder, and b) tell JetReader how to create the same folder structure (author/series/file, probably also with a pattern in the file name, like [series index] - [title], or something). Does that sound like a good solution, or do you have other suggestions?

I was thinking of a workflow of connecting the reader to my PC and using Calibre to manage the books in bulk on the boox (copy to boox/delete from boox) so being able to specify the download directory (eg Books) would make that simpler.

Having the option to also match the folder structure when downloading using Jetreader would also be ideal but more important would be supporting/updating the .driveinfo.calibre & .metadata.calibre files so any books downloaded or deleted by Jetreader would show up when connecting via Calibre and any books copied/deleted to/from the boox would be updated in Jetreader (so keeping the two connection methods in sync).

In general I think managing a large number of books on the device is easier on the larger PC screen using Calibre then directly on the device with the Jetreader library function being used more to browse the downloaded books library to select a book to read or when at home to browse the Calibre server to select a book to download and read.

Alternatively if your vision for the app is to have it manage locally a small subset of a main Calibre library (i.e books read/being read) then another option could be to support in addition to the remote Calibre server a local point in time copy of the Calibre database & books on the device to enable browsing and downloading from the local "main library" when connectivity to the remote Calibre server is not possible.

[Haudek]

I used the third code.