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Fenster is a fasting clock. Hours on, hours off. No streaks, no scores.
On your device. Fenster has no accounts and no servers. Deleting the app deletes your data.
Apple Health has no fasting data type, and Fenster does not fake one. Health receives only the weight entries you explicitly save.
You are past your target and still fasting. The window stays open until you close it.
Fenster asks with a notification once a window has been open well past its target. Close it from the notification or in the app; the log keeps the true duration.
Windows of 18 hours and up, custom hours, and stats are part of the one-time lifetime unlock. 16:8 and 12:12 are free forever. If you answered the safety questions with "one or more apply," windows above 14 hours stay off.
Open the unlock screen and tap "Restore purchase." The entitlement is tied to your Apple ID.
"Start my fast in Fenster" and "End my fast in Fenster" work with Siri, Shortcuts, the Action Button, and the Control Center control.
Fenster is a clock, not a clinic. Stop if you feel unwell. Do not skip prescribed medicine to keep a window. The app is not for anyone under 18, pregnant or breastfeeding, with an eating-disorder history, with type 1 diabetes, taking insulin, sulfonylureas, or SGLT2 inhibitors, or with advanced kidney, liver, or unstable heart disease.