Twitter cofounder Jack Dorsey unveils new app on heels of Bitchat launch

Twitter cofounder Jack Dorsey has unveiled a new application named ‘Sun Day’ that tracks UV exposure and vitamin D intake, according to his post on X.

Currently available via TestFlight on iOS, the app aims to provide personalised, accurate estimates while remaining conservative for safety.

It appears as small and medium widgets for the user’s home screen. The founder has made it available in the public domain, and its code is on GitHub for anyone to clone.