Jack Dorsey launches Sun Day to track UV exposure and Vitamin D intake, following his Bluetooth-based messaging experiment ...

Jack Dorsey is shipping. On Sunday, the Twitter co-founder shared a link on X (formerly Twitter) to a new app called Sun Day, ...

Jack Dorsey has launched Sun Day, an iOS app that tracks UV exposure and estimates vitamin D levels based on location, skin type, and clothing. This release follows his encrypted messaging app, ...

The app is open source, with its code published on GitHub, and it’s the latest in Dorsey’s experimental “weekend builds” — ...