I built this originally last year because I was frustrated that epubs even though they are digital are not being fully utilized.
I also read on many different platforms and I wanted all of my books to automatically sync.
I also have a bunch of friends who read the same books, so I built a little chatroom that you can get into if you all have the same book.
Lately voice models have gotten really good. So I also incorporated on device models which reads the book to you as an audiobook.
The app is in Tauri and using InstantDB for the database and backend sync. Really love the work stopachka and folks are doing with that.
Rust helps in doing a lot of the heavy lifting and onnx runtimes are great for cross platform model loading.
My kids also read on it so there is a pet (a cat or a dog) which can be a companion while you read and they move around and animate and tell you how many pages are left based on it's position on the page.
Long term I want to publish books from independent authors on this and have a directy publishing model but that's not there now.
Anyway, let me know if I can answer any questions about reading, rust, architecture, local models etc etc.
p.s. My fav author is Leo Tolstoy.