In an exciting development for health-conscious individuals, Jack Dorsey, the co-founder of Twitter, is diving into the world of app development with a new focus. Following the recent launch of a Bluetooth messaging application, he has now introduced an innovative tool named Sun Day, designed to assist users in monitoring their UV exposure and vitamin D levels.
This new application is currently accessible through TestFlight for iOS users, and its source code is available on GitHub, allowing developers to explore and modify it as they see fit.
Dorsey is embracing the trend of vibe-coding, opting for an open-source coding platform known as Goose, rather than more conventional tools like Cursor or Claude Code. This choice reflects a growing movement among developers to utilize community-driven resources for app creation.
Sun Day is user-friendly and provides essential information about the UV Index in your area, along with additional details such as cloud coverage and the timings for sunrise and sunset. Users can select their skin type from a range of six options and indicate their clothing style. With this information, the app calculates the safe duration for sun exposure to prevent skin damage.
The application also tracks your minimum vitamin D intake. To begin monitoring your UV exposure, simply tap the “Track UV exposure” button. Once your session concludes, the app will provide insights into the amount of vitamin D you have absorbed during that time, as well as throughout the day.