The PaperMono project is an open-source firmware for the M5Stack PaperMono e-paper device, turning it into a household shopping list that syncs with a mobile web app. The device, featuring a 3.97" e-paper touchscreen, displays a shopping list grouped by aisle, allowing users to tick off items or add new ones using the on-screen keyboard. A small server stores the list, remembers item aisles, and can optionally auto-sort new items. Users can access and manage the list from their phone by visiting a web page, and the project includes documentation for deployment using systemd and Docker, with a complete working app written in approximately 2,400 lines of C++.