ScalinYour weight history stays in Scalin on your devices and in Apple Health when you allow it. Scalin transfers history between your iPhone and paired Apple Watch using Apple's WatchConnectivity; settings and goals also sync through your iCloud. We do not operate a server that receives your weigh-ins. RevenueCat handles subscription validation using a random support ID and purchase information. Usage analytics through Firebase are described below; they contain no weight or Health data.
1. Who we are
Scalin is developed by Gleb Matsko, an individual developer based in Serbia ("we", "us"), the data controller for the processing described below. Contact: support@scalinapp.com.
2. What is collected, and what is not
| Data | Leaves your device? |
|---|---|
| Your weigh-ins, trend, goals, streak | Between your own devices through Apple services; not sent to us or RevenueCat |
| Apple Health data (body mass) | Kept in Health and Scalin on your devices; not sent to us or RevenueCat |
| Your height, BMI, calories, diet | Never asked for. The app does not have them |
| Name, email, phone, account | Never asked for. There are no accounts |
| App usage events, device model, OS and app version, approximate country | Yes — to Google Analytics for Firebase, pseudonymously |
| Random support ID and purchase information | Sent to RevenueCat for subscription access, restoration and subscription analytics |
| Payment details | Handled by Apple. We never see them |
3. What stays on your device
Your weigh-ins (weight, date, time and notes), goals, preferences and character history are stored in the app's shared container for Scalin and its widgets on each device. WatchConnectivity transfers this data between your iPhone and paired Apple Watch. Apple's iCloud key-value store carries settings, goals, setup state and cached subscription access under your Apple Account. We cannot access your iCloud data. Apple's own privacy policy and iCloud terms apply to these services.
4. Apple Health (HealthKit)
With your explicit permission, Scalin reads body-mass samples from Apple Health and writes your weigh-ins back to it, so your history is on the chart from day one and smart scales that already sync to Health appear in Scalin on their own.
- Health data is used only to show you your own weight, trend and progress inside the app.
- Health data is never sent to us, to Google, to Firebase, to any analytics service or to any other third party.
- Health data is never used for advertising, marketing or use-based data mining beyond your own experience in the app.
- Health data is never sold or disclosed to data brokers or information resellers.
Granting Health access is optional. You can continue setup and log readings manually without it. You can review or withdraw Scalin’s Health permissions in Apple Health or your device’s privacy settings.
5. Usage analytics
Scalin uses Google Analytics for Firebase to understand which features are used and improve the app. Google acts as our processor for this data.
What is sent:
- A randomly generated app instance identifier. This is a pseudonymous identifier for an app installation;
- Device model, operating system version, app version, device language and screen size;
- Approximate location — country or region, derived from the IP address of the connection;
- Events describing use of the app: sessions, screens opened, features used, subscription screen shown, onboarding completed, and similar;
- Subscription purchase and restoration outcomes, plus verified in-app purchase transactions recorded by Firebase, including the product, currency and purchase value. Scalin does not attach your support ID or RevenueCat user ID to these analytics events.
What is never sent: your weight, any individual weigh-in, your trend, your goals, your Apple Health data, your name, your email address or your precise location. Events record actions such as saving a reading or opening a goal, without their contents or values.
Scalin does not use the Advertising Identifier (IDFA), shows no App Tracking Transparency prompt, and does not track you across other companies' apps or websites. There is no advertising network in the app.
How to turn it off: analytics can be disabled in the app under Settings → Privacy & data → Share usage data. Turning it off stops collection on that device and resets locally stored analytics data. It does not delete events already received by Google. You may also object at any time by writing to support@scalinapp.com.
Google's own handling of this data is described at firebase.google.com/support/privacy and policies.google.com/privacy.
6. Purchases
Subscriptions are sold and billed by Apple. We do not receive your card details or Apple Account email. Scalin uses RevenueCat to validate purchases, restore access and report subscription status. It receives a random app user ID, purchase and receipt information, and technical information needed by its SDK. The ID appears as Settings → About Scalin → Support ID and is stored in Keychain, including iCloud Keychain when enabled, so a reinstall does not lose access. We do not attach weight or Health data to it.
Delete Scalin data keeps this subscription record and support ID. It does not cancel billing. You can manage or cancel your subscription in Apple's subscription settings, including from the deletion screen. For questions about purchase records, contact support@scalinapp.com. RevenueCat's processing is described in its privacy policy.
7. Notifications
If you allow them, Scalin sends one type of local notification: the morning reminder to weigh yourself. It is scheduled on your device and never sent from a server. There are no marketing notifications, ever. Turn them off in the app's settings or in iOS Settings.
8. Legal bases (EEA and UK)
| Purpose | Basis |
|---|---|
| Running the app; storing your weigh-ins on your device | Performance of a contract, Art. 6(1)(b) GDPR |
| Reading and writing Apple Health data | Your explicit consent, Art. 9(2)(a) — withdrawable in iOS Settings |
| Usage analytics | Our legitimate interest in maintaining and improving the app, Art. 6(1)(f) — you may object, or switch it off in the app |
| Subscription validation and restoration | Performance of a contract, Art. 6(1)(b) GDPR |
| Complying with tax, accounting and legal obligations | Art. 6(1)(c) |
9. Retention
Scalin history stays until you delete it. Settings → Privacy & data → Delete data → Delete Scalin data removes weigh-ins, notes, goals, preferences, character history, local Health cache and temporary CSV exports. A minimal reset marker without weight, notes or measurement dates is retained to prevent old device copies from restoring deleted history. The deletion reaches paired and iCloud-connected devices when they next connect. Offline devices can retain their old copy until then.
Original Apple Health readings and files you previously shared are not deleted by this action. Automatic Health import stops until you choose to import again. Your subscription record and support ID remain for billing and restoration; Apple and RevenueCat retain purchase records under their applicable terms and obligations.
Our retention limit for event-level analytics is 14 months. Aggregated reports that no longer identify an app installation may be retained longer. Turning off analytics stops future collection on that device; it does not itself remove events already received by Google.
10. International transfers
Apple processes device sync and Health data under your Apple Account settings and its terms. RevenueCat processes subscription information as described in its privacy policy, which includes information on international processing and safeguards. We do not send weigh-ins or Health samples to RevenueCat.
Usage analytics data are processed by Google LLC and its affiliates, including in the United States. Those transfers rely on the European Commission's Standard Contractual Clauses and, where applicable, the EU–US Data Privacy Framework, as set out in Google's data processing terms.
11. Your rights
You have the right to access, correct, erase, restrict and object to the processing of your personal data, and to data portability. In practice:
- Your weight data is already entirely in your hands: view and edit it in the app, export it as CSV in Settings, delete individual entries, or use Delete Scalin data. See Retention above for sync timing and data kept outside Scalin.
- Analytics data: switch it off in the app, or email us. To have data already collected for your installation deleted, contact us so we can explain what information is needed to locate it. Analytics uses a pseudonymous app instance identifier; your subscription Support ID is not linked to it.
- Subscription records: contact support@scalinapp.com with your Support ID for requests concerning information held by us or our subscription service provider.
- You may lodge a complaint with your local supervisory authority.
California residents: we do not sell or share personal information as those terms are defined by the CCPA/CPRA, and we do not use it for cross-context behavioural advertising. The categories collected are identifiers (a pseudonymous app instance ID and random support ID), purchase information, internet or network activity (in-app usage) and coarse geolocation (country). None contains your weight history.
12. Security
Your data is protected by the device encryption iOS and watchOS provide, and you can add a Face ID / Touch ID lock to the app in Settings. Subscription information is sent to RevenueCat over TLS. Analytics data is sent to Google over TLS. Because your weigh-ins are never transmitted to us, there is no server-side database of your health data that could be breached.
13. Children
Scalin is not directed at children under 13 (or the equivalent minimum age in your country) and we do not knowingly process their data. Check the App Store listing for the age rating in your region.
14. Third parties
Apple provides purchases, device sync, iCloud and Apple Health under Apple's privacy policy. RevenueCat provides purchase validation and subscription management under its privacy policy. Google provides Analytics for Firebase as our processor. There is no advertising network or data broker in the app.
15. This website
scalinapp.com is a static site. It sets no analytics cookies and runs no website analytics. Fonts and images are hosted with the site; visiting does not load Google Fonts. Our hosting provider, Vercel, processes technical request data such as IP addresses to deliver and secure the website. See Vercel’s privacy policy. Following a link to the App Store or another website is subject to that provider’s policy.
16. Changes to this policy
The current version is always at scalinapp.com/privacy with the date at the top. If a future version of Scalin processes anything materially differently, this page will be updated before that version ships, and where the law requires consent, the app will ask for it first.
17. Contact
Gleb Matsko, Serbia
Email: support@scalinapp.com