Jack Dorsey's latest app monitors your sun exposure
What's the story
Twitter co-founder Jack Dorsey has launched a new app called Sun Day, aimed at helping users monitor their UV exposure and Vitamin D intake. The app is available for iOS via TestFlight and its code can be accessed on GitHub for anyone interested in cloning it. Dorsey's latest venture comes just weeks after he released Bitchat, a Bluetooth-based messaging app.
Development process
Dorsey's coding tool of choice
Unlike many other developers who use tools like Cursor, Claude Code, or Windsurf for coding, Dorsey has opted for an open-source coding tool known as Goose. This unique approach reflects his innovative mindset and desire to explore different avenues in the app development process. The Sun Day app is a testament to this unconventional strategy as it offers a simple yet effective way of tracking UV exposure and Vitamin D intake.
App features
How does it work?
Sun Day provides the UV Index for your location, along with information on cloud cover, sunrise, as well as sunset timings. Users can select their skin type from six options and specify what kind of clothing they're wearing. Based on these inputs, the app calculates how long one can safely expose their skin to sunlight before burning.
Extras
Monitoring your vitamin D intake
Apart from tracking UV exposure, Sun Day also monitors your minimum Vitamin D intake. Users can begin a session by tapping on the 'Track UV Exposure' button. Once the session ends, the app displays how much Vitamin D has been absorbed during that time and throughout the day. This additional feature makes Sun Day a comprehensive tool for managing Sun exposure and Vitamin D levels effectively.