Lumm is a mobile application designed for couples to send a non-verbal signal to each other. Its primary function is to provide a zero-text check-in, allowing one user to indicate they are thinking of their partner without composing a message or starting a conversation. The app replaces written communication with a single button that, when tapped, sends a haptic pulse and a soft glow to the partner's phone. The main features of Lumm include a one-time pairing process using a shared code, after which no further setup is required. The interface consists of a single button; tapping it triggers the haptic and visual notification on the paired device. If the partner is not currently using the app, the signal is delivered the next time they open it. The app is intentionally designed without chat, messaging, or emoji selection capabilities. Typical use cases involve moments when a text message feels like too much effort or might initiate an unwanted conversation, but complete silence feels insufficient. The workflow is simple: users pair once, and then one user taps the button whenever their partner is on their mind. The partner then receives the silent notification, conveying the message without any written content. The app is built for mobile devices and requires both partners to install and open the application to establish the initial connection.