Privacy Policy

TrendWeight AI · Last updated July 2, 2026

TrendWeight AI ("the app", "we", "us") is a personal weight-tracking app that shows a smoothed weight trend and short AI-generated explanations of your day-to-day changes. This policy explains what data the app handles and why. We keep this deliberately minimal: the app exists to track your weight, and we don't want any more data than that requires.

Information we collect

• Account. The app signs you in with an anonymous account — a random identifier. We do not require or collect your name, email address, or a password to use the app.
• Weigh-ins. The weight values you enter, their date/time, any lifestyle tags you attach (e.g. sodium, sleep), the smoothed trend value computed from them, and the AI insight text generated for that entry.
• Profile you provide. Optional details you enter during onboarding or in settings: display name, gender, height, goal weight, and your answers to the reflective onboarding questions. These are used to personalize the experience and the AI insights.
• Health app data (optional). If you turn on the Health integration, the app reads body-weight samples only from Apple Health (iOS) or Health Connect (Android), with your explicit permission, and turns them into weigh-ins. You can disconnect at any time in Settings. This data is used solely inside the app and is never used for advertising.
• Subscription status. Purchases are handled by the app stores and RevenueCat. We receive your subscription status and an anonymized purchase identifier — not your full payment card details.

We do not collect your email, precise location, contacts, or advertising identifiers, and the app contains no third-party advertising or tracking SDKs.

How we use your data

• To calculate and display your weight trend, statistics, and goal projections.
• To generate the daily AI insight explaining your fluctuations.
• To manage your subscription and app access.
• To keep the service working reliably.

AI processing

To generate each insight, the app sends a small, numbers-only payload to Google's Gemini API through our secure backend: your recent weight and trend values, the tags on the entry, your goal weight, your display unit, and the hour of day you weighed in. Your name and identity are not included. This data is processed only to produce your insight text and is not used to show you ads.

Where your data is stored & who processes it

We use a small number of service providers to run the app:

• Supabase — hosts the database and anonymous authentication that store your weigh-ins and profile.
• Google Gemini API — generates the AI insight text from the numeric payload above.
• RevenueCat and the Apple App Store / Google Play — process and manage subscriptions.
• Apple Health / Google Health Connect — only if you enable the optional import; the weight data stays under your device's health permissions.

Data sharing

We do not sell your personal data, and we do not share it for advertising. Data is shared only with the processors above, strictly to operate the features you use.

Data retention & deletion

Your data is kept until you delete it. You can permanently erase your account and all associated data at any time from within the app: Settings → Delete account. This removes your account and cascades to delete every weigh-in, your profile, and your AI-usage records. You may also contact us to request deletion.

Security

Data is encrypted in transit. Database access is protected with row-level security so that each account can only read and write its own records.

Children

TrendWeight AI is not directed to children under 13 (or under 16 in the EEA/UK), and we do not knowingly collect data from them.

Changes to this policy

We may update this policy from time to time. Material changes will be reflected by the "Last updated" date above.

Contact

Questions or requests about your data? Contact us at [email protected].