The Calibre Content Server
Related but slightly off topic:Am I the only one who is turned off to calibre due to how "heavy" and clunky it feels?  I suspect this is due to the program being written in Java. I think the author does great work maintaining the project but frankly wish it was more modern.Perhaps this is a good side project for me to delve into ;)EDIT: thanks to users who clarified that Calibre is written in python.