CK-IN
Johannes Duo Health & Fitness iPhoneiPadiPod touch
CK-IN is a free Health & Fitness app for iPhone and iPad by Johannes Duo. Requires iOS 17.0. Updated January 21, 2026.
- Price
- Free
- on the App Store
- Size
- 85 MB
- Age 4+
- Updated
- Jan 21
- 2026 · v1.1
Screenshots
About CK-IN
CK-IN, Build Consistency. Stay Accountable. Don't Skip. CK-IN is a daily fitness accountability app built to help you show up even on the days you don't feel like it. This isn't about perfect workouts, calorie counting, or complicated plans. CK-IN is about consistency, commitment, and people who notice when you don't show up. By using this app, you agree to our Terms of Use: https://www.ck-in.co/terms.html and Privacy Policy: https://www.ck-in.co/privacy.html
What’s new
Version 1.1 · Updated January 21, 2026
What's New in Version 1.1 We’ve made critical improvements to help you stay consistent: Timer Intelligence Update: Your workout timer now tracks precisely even when the app is in the background or your phone is locked. No more paused timers. Smart Completion Alerts: You will now receive a "Workout Complete" notification exactly when your planned duration ends, so you know it’s time to check out—even if your phone is in your pocket. Performance Improvements: Enhanced session stability and faster load times. Stay consistent. Stay locked in.
App privacy
The developer, Johannes Duo, reported these privacy practices to Apple.
Data Linked to You
The following data, which may be collected and linked to your identity, may be used for the following purposes:
- Health & Fitness: Fitness, Health
- Contact Info: Email Address, Name, Phone Number
- User Content: Photos or Videos, Other User Content
- Identifiers: User ID, Device ID
- Usage Data: Product Interaction, Other Usage Data
- Diagnostics: Crash Data
- Location: Precise Location
Used for: Analytics, App Functionality
Data Not Linked to You
The following data, which may be collected but is not linked to your identity, may be used for the following purposes:
- Diagnostics: Performance Data, Other Diagnostic Data, Crash Data
- Usage Data: Product Interaction
- Contact Info: Email Address, Name, Phone Number
Used for: Analytics, Product Personalization, App Functionality
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| App | Rating | Price | Last updated | Compare |
|---|---|---|---|---|
| CK-IN | – | Free | January 21, 2026 | |
| Mirrocle | – | Free | May 15, 2026 | Compare |
| Spotter: AI Lift Coach | 5.0 / 5 (8) | Free | Aug 26, 2026 | Compare |
| Luvra AI - Skincare Advisor | 5.0 / 5 (1) | Free | Nov 30, 2025 | Compare |
| TicuraAi | 5.0 / 5 (2) | Free | Jan 26, 2026 | Compare |
| Shimmer: Period & Hormones | – | Free | May 1, 2026 | Compare |
| BiomarkersIQ | 5.0 / 5 (3) | Free | Sep 12, 2026 | Compare |
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