Health, home and travel decision
Goldn - Tan & UV
A minimal local iOS replacement (camera, simple on-device image metrics, UV lookup, timer, local journal) is realistic for a capable developer, but reproducing the polished on-device analysis, subscription UX, and App Store polish at parity would be time-consuming and is not fully covered by available public artifacts.
View on the App Store↗$8.99/mo
$108/yr
Read off the official pricing page.
$100one-off160 h to build
$20/mo3 h/mo upkeep
On cash alone, building overtakes the subscription at 4 seats.
No open-source build does this yet
Nothing published replaces this one, so a replacement starts from an empty file. Here is what it would have to cover.
What a replacement has to do
- Take a photo, analyze skin metrics on-device, fetch real-time UV index for current location, start/manage exposure timer based on phototype, and save sessions to a local journal.
What it still won’t have
- Polish and design quality of a consumer App Store product
- App Store distribution experience and user acquisition handled by the vendor
- Any proprietary on-device skin-analysis models or tuned heuristics the vendor uses
- Integrated in‑app billing history and analytics provided by the published app
What remains hard
- Product polish and ongoing maintenance
First-year cost
Keep paying
Paying is—cheaper in year one.
On cash alone, building overtakes the subscription at 4 seats.
Money you would actually spend
Time you would spend
—
What you would spend
What we assumed
The verdict above measures whether you could build it. This one is only about money.
Runnable build prompt
Build an iOS SwiftUI app (Swift 5, Xcode) that: 1) captures photos with the camera and stores them locally; 2) implements on-device skin analysis using Core Image / Vision to compute simple metrics (tan, redness, evenness) and exposes them via a results view; 3) fetches UV index for device location from a public UV API (configurable base URL/key) and maps values to risk levels; 4) provides an exposure timer computed from phototype with local notifications; 5) stores session history in Core Data and shows a timeline; 6) implements StoreKit subscriptions for unlocking features (mocked for development); exclude: no server-side image uploads, no machine-learning model training, no App Store submission tasks. Include error handling for camera, location, and network failures, and provide unit tests for timer logic, UV mapping, and data persistence plus basic UI tests for capture and session creation.
How we checked
How the score was reached
- Partly verdict base52
- Price verified on pricing page+3
- 3/3 assessment runs agreed+4
- Evidence score59
The base comes from the verdict. Everything under it is a check that either happened or did not, and each one is a fact frozen in this record rather than a judgement made at render time - so the same evidence always produces the same number.
How scoring works →Cited sources · 1
Every page the run actually retrieved.
- official productGoldn - Tan & UV Tracker (App Store)
Integrity checks
What held up, and what did not.
