Fönster: Wake Window Tracker
Next sleep window, calculated
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
At 3 a.m. you don't want a dashboard. You want one answer: when should they sleep next?
Fönster calculates the next sleep window instantly — from age and your own logs, using the age range as a starting point. Didn't fall asleep? One tap recalculates a new window on the spot. No rigid sleep schedule to set up — the wake window is the schedule, tuned to your baby's own bedtime rhythm. A baby tracker that answers instead of asking. No forms. No waiting days.
ON YOUR LOCK SCREEN
The next window sits on your Lock Screen and Home Screen — you don't even open the app. The countdown updates itself, and when the other parent starts a sleep, your widget says who did it. No notification. Nothing that wakes anyone.
BUILT FOR TWO
Invite the other parent with a link — no account needed. You see the same log instantly, and either of you can start and end a sleep without "another user" errors. The second caregiver is always included at no extra cost. Grandma can have read-only mode.
YOUR DATA IS YOURS
Everything lives on your phone first. Export (CSV) works even without a subscription. We never hold old data hostage. No account to create. No ads.
LOG ONE-HANDED
Sleep, breastfeeding or bottle, diapers and naps with big buttons, in dark mode — built for nights.
Logging is free forever — sleep, feeds, diapers, sharing and export.
What you pay for is the calculation: the next sleep window and the recalculation when they don't settle. Your first personalized sleep window is included.
After that preview it becomes a subscription: $39.99/year or $7.99/month. The yearly plan starts with a 14-day free trial, then renews automatically unless you cancel in the App Store.
Fönster gives general guidance from age and your own logs. It is not medical advice — talk to your pediatrician if you are worried.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Fönster now notices when an old sleep window can no longer describe your baby's current rhythm. Add when your baby last fell asleep or woke up, and Fönster calculates a useful window again.
We've also improved large-text layouts so the main actions stay reachable on smaller iPhones.
The developer, Next Epic Co., Ltd., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Health & Fitness
- Purchases
- Contact Info
- Identifiers
- Other Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Next Epic Co., Ltd.
- Size
- 70.4 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 5 more
- English, Danish, Finnish, Korean, Norwegian Bokmål, Swedish
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- In-App Purchases
Yes
- Monthly $7.99
- One year $39.99
- Copyright
- © 2026 Next Epic Co., Ltd.
