Stop paying $80/year for a timer. Solstice tracks your fast with zero paywalls, 5 biological metabolic stages, and ambient displays on your Nightstand, Lock Screen, and Apple Watch.
You shouldn't have to unlock your phone and launch a heavy app just to know if you're burning fat. Solstice lives quietly in your peripheral vision.
Snap your iPhone horizontally on MagSafe while sleeping. Solstice displays your current metabolic stage and time to goal in luminous OLED amber tones all night long.
Start or stop your fast right from your wrist. View circular and rectangular progress complications across your favorite watch faces with seamless background syncing.
One-tap toggle directly in iOS 18 Control Center, Lock Screen quick-action slots, or mapped to the iPhone 15/16 Action Button for zero-friction fast logging.
Glanceable metabolic countdowns powered by native WidgetKit timelines. Zero continuous battery drain, no servers, and no background location tracking.
Drag the slider or click a milestone to explore what happens inside your cells as fasting hours progress.
Your cells initiate an intracellular cleaning process called autophagy. Damaged mitochondria, misfolded proteins, and senescent cells are broken down and recycled into fresh cellular energy.
Why thousands of fasters are ditching bloated subscription apps in favor of Solstice.
| Feature | ☀️ Solstice | Zero / Simple / Fastic |
|---|---|---|
| Subscription Price | $0 (Free Forever Core) | $69.99 – $99.99 / year |
| User Privacy & Accounts | 100% On-Device, No Account | Data sold to ad brokers |
| 5 Metabolic Stages | 100% Unlocked for Everyone | Paywalled behind Pro tier |
| Onboarding Experience | Instant Launch (Tap & Fast) | 15-minute quiz & paywall traps |
| iOS 18 StandBy Nightstand | Native Overnight Display | Not supported |
| Apple Watch Complications | Standalone Watch App included | Requires premium subscription |
| Battery Impact | Native Swift (Negligible) | Heavy WebView battery drain |
Fasting is only half the equation. How you break your fast determines your energy, digestion, and long-term metabolism. Meet your intelligent break-fast companion.
Snap a photo of your break-fast plate. Multimodal AI instantly breaks down protein, healthy fats, and net carbs without tedious manual logging.
Avoid post-fast insulin spikes, brain fog, and digestive cramps with personalized meal safety ratings based on your fasting duration.
Correlates what you eat during your feeding window with how effortless your next fasting cycle feels.
Be the first to test Solstice AI meal tracking with exclusive lifetime founder pricing. Core fasting stays free forever.
Everything you need to know about Solstice, fasting science, and our privacy guarantee.
Yes, completely. All core fasting tracking features — including the 24-hour circular dial, 5 metabolic stages, streak calendar heatmap, Apple Watch app, StandBy mode, and interactive widgets — are 100% free with zero paywalls and zero ads forever.
Solstice operates entirely on your device using Apple's native Core Data framework. We do not require an account, we do not have remote user databases, and we do not bundle any third-party tracking, analytics, or advertising SDKs. What you track stays on your device.
Autophagy (cellular self-cleaning) is a Nobel Prize-winning biological mechanism that typically kicks in around hour 18 of fasting. When nutrient intake drops, cells clear away damaged mitochondria and misfolded proteins. Solstice calculates your estimated entry into this stage in real time.
On iOS 18+, when your iPhone is connected to a MagSafe charger and placed in landscape orientation, iOS activates StandBy mode. Add the Solstice widget to your StandBy screen to see an ambient, low-light display of your fasting progress and countdown to breakfast without blinding your eyes at night.
No. Solstice is built with 100% native Swift and SwiftUI. Unlike apps built with heavy web containers that run background processes, Solstice schedules native WidgetKit timelines that consume zero background battery.
Yes. Solstice provides one-tap presets for 14:10, 16:8, 18:6, 20:4 (Warrior), and OMAD (23:1), or you can drag the circular dial wheel to customize any target interval up to 72 hours.
Join thousands of mindful fasters enjoying clean, distraction-free fasting with zero subscriptions and complete privacy.
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