Caffy · Caffeine Tracker

2026Health & Fitness

Shows how much caffeine is in you right now and when you'll be ready to sleep tonight, using the decay model the FDA and EFSA cite, adjusted to your own half-life.

Dashboard with 222 mg of active caffeine
Sleep prediction
Weekly insights
SwiftUISwift ChartsWidgetKitSupabaseRevenueCat
App Store

Problem

Most caffeine apps count cups. The question people actually have is what that 4 pm coffee means at midnight, and the answer depends on the person: age, pregnancy, oral contraceptives, smoking and sensitivity all change how long caffeine stays.

Solution

Caffy models it: a 45 minute absorption phase, then exponential decay on a personal half-life. The live curve becomes a sleep readiness score before bedtime, a focus window for when caffeine peaks, and detox programs for cutting down gradually. Six widgets put the numbers on the Home Screen and the Lock Screen.

Outcome

Caffy was my first app on the App Store, released in June 2026. It runs in five languages (English, Turkish, German, Spanish and Japanese), is anonymous on first launch, and syncs between devices through Supabase.