Privacy & Technology
Why an offline smart scale app protects your health data
Most smart scale apps mandate cloud accounts, third-party trackers, and remote database uploads. Scale Metrics takes the opposite approach: 100% offline direct Bluetooth sync with strictly on-device data storage.
Why do most smart scale apps require cloud accounts?
Commercial scale apps often require email registration and online accounts to build user profiles, monetize health data, and push recurring wellness subscriptions. Your daily weight, body fat percentage, and biometric history are transmitted to remote servers.
This creates unnecessary privacy vulnerabilities:
- Remote data exposure: Any centralized health database is subject to server breaches, corporate ownership changes, or third-party data sharing.
- Aggressive tracking: Many companion apps embed commercial advertising identifiers, behavioral trackers, and marketing SDKs.
- Internet dependency: If Wi-Fi is down or servers experience outages, syncing measurements or viewing history fails.
How does offline Bluetooth sync work?
Smart scales measure weight and bioelectrical impedance. Compatible scales (such as Xiaomi Mi Body Composition scales) broadcast this measurement data locally through Bluetooth Low Energy (BLE) advertising packets.
Scale Metrics utilizes Apple's native Core Bluetooth framework to listen for these local broadcasts directly on your iPhone. When you step on the scale:
- The scale broadcasts weight and impedance values via BLE.
- Scale Metrics captures the signal directly on your iPhone within seconds.
- The calculation of body composition estimates occurs locally on your iPhone processor.
- No cellular data, Wi-Fi network, or cloud server is ever contacted.
Where is your measurement history stored?
All historical weigh-ins, body score calculations, and multi-period curves are stored exclusively in your iPhone's local sandbox storage. Your data never leaves your device.
By keeping storage strictly local:
- You retain full ownership and physical control of your sensitive biometric history.
- The app works in remote cabins, gyms without Wi-Fi, airplane mode, or basement bathrooms.
- Deleting the app completely purges all stored measurement records from your phone.
No advertising IDs, analytics SDKs, or external calls
Scale Metrics includes zero advertising SDKs, zero third-party telemetry frameworks, and zero behavioral tracking tools. The app makes no outbound network connections for user analytics.
Independent apps designed around local-first principles prove that modern fitness and wellness tracking does not require sacrificing personal privacy.
Summary & Download
If you own a compatible Xiaomi Mi Body Composition scale and want clean, accurate, distraction-free tracking without sacrificing your biometric privacy, Scale Metrics was built for you.