Calibre is a free and open source ebook manager.
The server includes a simple and elegant browser front-end that allows you to search for and download books from your library. It also has a mobile-friendly site built in, making it easy to download books straight to an e-reader – even to ones with only the most basic web functionality.
How To Create a calibre Ebook Server on Ubuntu 20.04
How To Create a calibre Ebook Server on Ubuntu 18.04
How To Create a calibre Ebook Server on Ubuntu 14.04
Scale up as you grow — whether you're running one virtual machine or ten thousand.

From GPU-powered inference and Kubernetes to managed databases and storage, get everything you need to build, scale, and deploy intelligent applications.
