Privacy Policy
Last updated: October 28, 2026
Scale Relay is designed with your privacy in mind. Scale readings are processed locally on your device and are not stored on Scale Relay servers.
Bluetooth
The app uses Bluetooth to read measurements from supported scales. Weight and impedance are processed locally to calculate body composition metrics.
Accounts
Garmin Connect is used only when you choose to upload a measurement. The Xiaomi Body Composition Scale S400 requires a one-time Xiaomi authorization to retrieve its Bluetooth encryption key. Authentication data is stored in the iOS Keychain.
Apple Health
Apple Health access is optional and requested only after you choose it as the measurement source. Scale Relay requests read access to weight, body-fat percentage, and BMI from the source you select and can send compatible values directly to your connected Garmin account. With "Save weigh-ins to Apple Health" turned on (Scale Relay 1.4 and later), it also writes weight, BMI, body fat and lean body mass from your Bluetooth scale to Health; nothing read from Health is ever written back, and there is no continuous background sync. Measurements waiting for a requested Garmin transfer or an Apple Health copy are held only in backup-excluded, protected local files and removed after delivery; switching measurement sources does not remove them. Health data is not stored on Scale Relay servers and is never used for advertising, analytics, marketing, or profiling.
Body Fat Adjustment (optional, Scale Relay 1.5)
To compare a body fat reference you enter (value, date and method) with the scale's own estimates, Scale Relay keeps the last 60 days of Bluetooth weigh-ins (time, weight, impedance, scale type and body fat before and after any adjustment) on your iPhone, also while the adjustment is off. Each reference keeps the few weigh-ins it was compared with and the sex, height and age at the time. All of this stays in backup-excluded, protected files on the iPhone and is never uploaded. Weigh-ins the adjustment applies to go to Garmin Connect and Apple Health with the adjusted body fat; the Apple Health samples also carry the scale's own estimate, the adjustment and the reference date and method as metadata. You can remove references in Settings › Body Fat.
Private app, privacy-friendly website analytics
The Scale Relay app does not include analytics, advertising, or tracking frameworks. This website uses Cloudflare Web Analytics for aggregate traffic and page-performance statistics. It does not use cookies, persistent identifiers, advertising profiles, or cross-site tracking. Scale measurements, form content, email addresses, and authentication data are not sent to website analytics.
Contact form
If you use the website contact form or the optional feedback form in the app, we receive your message and any email address or scale model you choose to provide. App diagnostics are included only with your permission and never contain measurements or authentication data; they say whether the optional Body Fat Adjustment is on, with its reference method and scale type, but no values or dates. Messages are delivered through a Firebase Function and Resend and are not used for analytics or advertising.
Support
Need personal help, want to share feedback, or have a scale you would like us to support? Contact us.
Already using Scale Relay? A rating on the App Store helps other Garmin users find it: Rate Scale Relay.
Read directly over Bluetooth:
- Mi Body Composition Scale 2
- Xiaomi Body Composition Scale S400 (model MJTZC01YM)
Through Apple Health: any scale whose own app saves weigh-ins to the Health app, including Withings, Renpho, Eufy, Etekcity and Zepp Life. Scale Relay reads what that app already wrote; it cannot add data the scale never recorded.
Common issues:
- Scale not detected: Enable Bluetooth, open Scale Relay, and wake the scale by stepping on it.
- No body composition: Measure barefoot and remain still until the measurement finishes.
- S400 setup: The S400 must already be paired in Xiaomi Home before one-time authorization in Scale Relay.
- Nothing on the Health tab: Open your scale's own app once after weighing so it writes to Apple Health, then pull down to refresh in Scale Relay.
- Garmin sign-in fails and you are in mainland China: Scale Relay signs in to connect.garmin.com only; Garmin China (garmin.cn) accounts are separate and not supported.
Disclaimer: Scale Relay is an independent app and is not affiliated with, endorsed by, or sponsored by Garmin Ltd., Xiaomi Inc., Apple Inc., Withings, Renpho, Anker Innovations (eufy), Etekcity or any other scale manufacturer. Garmin and Garmin Connect are trademarks of Garmin Ltd. Xiaomi and Mi are trademarks of Xiaomi Inc. Apple and iPhone are trademarks of Apple Inc.
