Twilight: simple sleep tracker

Twilight is the simplest sleep tracker you'll find that actually helps you build better sleep habits.

Sleep apps tend to overwhelm you with data you don't need. Twilight does the opposite. It tracks when you sleep and when you wake up, and shows you exactly what's improving and what isn't. Consistency & duration are the only sleep variables you actually control, and the metrics are built around that.

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THE METRICS

Every number in Twilight is there for a reason: to help you understand your trend or keep you motivated to stay consistent.

• Bedtime Rhythm: what % of nights you hit your target bedtime
• Wake Rhythm: what % of mornings you hit your target wake time
• Accuracy Score: how close your actual schedule matches your goal
• 7-Night Moving Average: smooths out outliers so you see the real trend
• Sleep Debt: cumulative deficit tracked over 30 and 90-day windows
• Weekday Breakdown: see if weekends are quietly wrecking your rhythm
• Duration Distribution: visualize how your nights cluster over time
• Streak: consecutive nights on schedule; the number that makes you not want to break it

When the streak hits 12 days and your bedtime rhythm reads 87%, staying consistent stops feeling hard. The data builds the habit.

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FEATURES

• NFC & QR Activation: tap a tag on your nightstand to start your session. No app-opening needed.
• Control Center & Siri: toggle sleep and wake from Control Center or with a voice command
• Wind-Down Timeline: a personalized 3-hour countdown with actions tied to your actual bedtime
• Apple Health Sync: your sleep sessions sync to Apple Health automatically
• Live Activity: session status on your Lock Screen and Dynamic Island
• Export your full sleep history in CSV or Markdown anytime

Coming soon: app & website blocking, full bi-directional Apple Health sync, smart alarm clock, automatic tracking, and more.

Everything stays on your device. No account, no subscription. The source code is open and public.