Health & Fitness
Helia
Sunlight, measured.
iPhone · iPad · Watch
The app
Sunlight, measured.
A vitamin D tracker that estimates what you actually synthesised, from the sun's real angle at your location, your skin type, what you were wearing and how long you stayed out.
The hero is a living sky that follows the weather and the hour. Every figure is presented as an estimate and carries a medical disclaimer, because that is exactly what it is. Your location is rounded to about a kilometre before anything is calculated.
Features
What it actually does.
Estimates from real solar geometry
A sky that tracks weather and time
Reads Apple Health on device
Accessibility-first type stack
Privacy
Health data is read live and never synced. Your location is coarsened to roughly a kilometre.
StorageOn device
SwiftData on-device, with opt-in private iCloud sync
Apple HealthRead only
HealthKit is read live on-device and never uploaded
LocationOnly when used
Coarse location, rounded to ~1 km, used for solar geometry
AnalyticsNone
No analytics of any kind.
Third partiesNetwork
Apple WeatherKit