Sun Day
Jack Dorsey's iOS UV tracker and vitamin D calculator, built with the Goose coding agent
About
Sun Day is an iPhone app (iOS 17+) that shows the current UV index for your location and estimates vitamin D production from logged sun sessions based on skin type and clothing, with a published methodology and privacy policy; the code is public domain on GitHub and the app was distributed via TestFlight. Dorsey released it two weeks after bitchat and said he built it with the open-source Goose agent rather than Cursor or Claude Code.
3.9 · 4 ratings