Health, home and travel decision
Arc
A single developer can reproduce the core diagnostic and local coaching features in a few months, but the full shipped product's mobile polish, content, and App Store distribution make a complete replacement harder and justify continued subscription for many users.
Visit website↗Built by Pritam, who ships 3 products in this index
Not priced
No pricing page we fetched carried a figure, so there is nothing to compare against. The build side is still real.
$100one-off140 h to build
$0/mo3 h/mo upkeep
No published price to break even against.
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
- User answers onboarding questionnaire → app computes chronotype and parameters → schedule engine produces daily protocol (peak focus windows, caffeine cutoff, light windows) → local storage of entries and history → UI shows live ring, charts, and sends timed notifications
What it still won’t have
- App Store-managed subscription handling and ecosystem discoverability
- Polish of the shipped mobile UX (animations, accessibility, edge-case polish)
- Curated science content, guides, and branded copy
- Established user reviews and trust/brand recognition
- Cross-device cloud sync (the product advertises local-first zero-cloud; any optional cloud sync would be missing)
What remains hard
- Product polish and ongoing maintenance
First-year cost
No published price
Arc does not publish a price we could read, so there is nothing to compare against. What building costs is below.
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 app (SwiftUI + Combine) with a local SQLite (GRDB) database that implements: (1) a 32-question onboarding flow storing responses locally; (2) a chronotype and scheduling engine that computes chronotype, caffeine-decay curve, morning light window, peak focus windows, and nightly wind-down time; (3) a local-only daily protocol screen with a live countdown ring, single-action briefing, and push/local notifications; (4) time-series charts and a single progress score; (5) export/import of local data (JSON). Out of scope: cloud sync, server-side analytics, and App Store submission. Include error handling, unit tests for the algorithm and storage layer, and UI tests for the main flows.
How we checked
How the score was reached
- Partly verdict base52
- 2 cited sources+1
- Evidence score53
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 · 2
Every page the run actually retrieved.
- official productARC — Circadian Rhythm & Sleep | Energy Tracker & Chronotype
- official pricingARC — Pricing
Integrity checks
What held up, and what did not.
