Privacy Policy

Last updated: February 17, 2026

Overview

Terrain Health (“we,” “our,” or “us”) respects your privacy and is committed to protecting the personal information you share with us. This Privacy Policy explains how we collect, use, and safeguard your information when you visit our website or use our iOS application (collectively, the “Service”).

Key principle: Terrain is designed as a local-first app. Your data is stored on your device by default. Cloud sync is optional and requires creating an account.

Information We Collect

Account Information (Optional)

If you choose to create an account, we collect:

  • Email address (for email sign-up)
  • Apple ID identifier (for Sign in with Apple — we do not receive your Apple password or real email if you choose “Hide My Email”)
  • Display name (optional, you can choose not to provide one)

Terrain Profile

When you take the terrain assessment quiz, we store:

  • Your quiz responses and calculated scores
  • Your terrain type (e.g., “Cold Deficient,” “Warm Excess”)
  • Your terrain modifier (e.g., “Damp,” “Shen Unsettled”)
  • Your wellness goals
  • Demographics (age, gender, ethnicity) — used only for content personalization

Safety Preferences

You may optionally disclose health-related information to help us filter content appropriately:

  • Pregnancy or breastfeeding status
  • Medications (blood thinners, blood pressure, thyroid, diabetes)
  • Dietary considerations (GERD, caffeine avoidance, histamine intolerance)

This information is used solely to show or hide relevant safety warnings on ingredients and routines.

Daily Check-ins and Progress

When you use the app's tracking features, we store:

  • Mood ratings (1–5 scale)
  • Symptom selections
  • TCM diagnostic signals (sleep quality, dominant emotion, thermal feeling, digestive state, menstrual cycle phase)
  • Routine completions and feedback (including duration and activity type)
  • Streak data and completion history
  • Program enrollment and progress

Tongue Reading Photos and Observations

The Tongue tab allows you to photograph your tongue for Traditional Chinese Medicine wellness pattern analysis. When you use this feature:

  • Photos are stored locally on your device in the app's private sandbox
  • With an account, photos are optionally uploaded to our cloud storage for cross-device sync
  • Cloud photos are automatically deleted after 14 days — only metadata (observations, patterns, dates) is retained long-term
  • Structured observations (tongue color, shape, coating, moisture) and TCM pattern interpretations are stored alongside each reading
  • When you sign out, local photos are cleared. Cloud photos are preserved until the 14-day auto-deletion or account deletion.
  • Photos can also be selected from your device's photo library (requires your permission) — selected photos are used solely for tongue analysis

AI-Powered Tongue Analysis (Optional)

With your explicit consent, tongue photos can be analyzed using AI to identify visual patterns. This feature:

  • Uses OpenAI's GPT-4o vision model — your photo is sent to OpenAI via our secure server for analysis
  • Your photo is encrypted in transit and not stored by OpenAI — it is discarded immediately after analysis
  • You must explicitly opt in before the first analysis (one-time consent)
  • You can disable AI analysis at any time in Settings — a manual observation option is always available
  • AI-generated observations (impression, quality score, per-observation notes, additional findings) are stored with your tongue reading

OpenAI processes the photo according to their privacy policy. OpenAI does not use API data to train their models.

Cabinet

Your saved ingredients, including which items you've marked as staples and when you last used them.

Health Data (Optional, with Permission)

With your explicit permission, we read the following from Apple HealthKit:

  • Step count — displayed alongside daily check-ins and used for activity trend tracking
  • Sleep duration and in-bed time — used to inform sleep quality trends and personalize daily recommendations
  • Resting heart rate — used as a TCM wellness signal (elevated may indicate heat/shen patterns; low may indicate cold/deficiency patterns)

HealthKit data is:

  • Read-only — we never write to HealthKit
  • Cached locally on your device as part of your daily log
  • Synced to the cloud only if you have an account (as part of daily log data)
  • Never used for advertising, marketing, or data mining
  • Never stored in iCloud
  • Never shared with third parties beyond Supabase (our database provider, if you enable cloud sync)

Location and Weather

With your permission, we use your location to fetch current weather conditions via Apple WeatherKit.

  • We do not store or transmit your precise location
  • Weather condition (e.g., cold, hot, humid) and temperature are cached on your daily log to personalize recommendations
  • Weather data display includes Apple Weather attribution as required by Apple
  • The app functions normally if you decline location permission

Notifications (Optional, with Permission)

With your permission, Terrain sends daily wellness reminders with terrain-specific micro-actions tailored to your body type. Notifications are entirely optional and require your explicit permission.

  • Notification content (reminders, micro-actions) is generated locally on your device from your terrain type — it is not fetched from a server
  • Your notification preferences (enabled/disabled, preferred times) are stored with your profile and synced if you have an account
  • You can disable notifications at any time in iOS Settings or within the app

Website Visitors

When you visit our website, we may collect standard web analytics data such as browser type, device type, pages visited, and referring URL via Vercel Analytics. We do not use invasive tracking or sell your data to third parties.

How We Use Your Information

We use the information we collect to:

  • Personalize your terrain-specific content, routines, ingredients, suggestions, and notification scheduling
  • Display relevant safety warnings based on your preferences
  • Track your progress and show wellness trends over time
  • Generate tongue reading interpretations and pattern analysis
  • Sync your data across devices (if you create an account)
  • Improve our Service and develop new features
  • Respond to your questions or feedback

Data Storage

Local-First Architecture

By default, all your data is stored locally on your device using Apple's SwiftData framework. This means:

  • Your data stays on your device unless you opt into cloud sync
  • The app works fully offline
  • Uninstalling the app removes your local data

Cloud Sync (Optional)

If you create an account, your data syncs to our cloud database (hosted by Supabase). Cloud-synced data includes:

  • User profile (terrain type, quiz responses, demographics, lifestyle preferences, notification settings)
  • Daily logs (mood, symptoms, diagnostic signals, routine feedback, cached health/weather data)
  • Progress records (streaks, completion history)
  • Ingredient cabinet (saved items, staples, usage dates)
  • Program enrollments and day progress
  • Tongue reading metadata (observations, patterns, AI analysis results — not the photo itself long-term)

Cloud-synced data:

  • Is stored on secure servers in the United States (us-west-1)
  • Is encrypted in transit using TLS
  • Is protected by row-level security — only you can access your data
  • Uses a last-write-wins sync strategy with per-table error isolation
  • Can be deleted by deleting your account

Tongue Photo Cloud Storage

Tongue reading photos are stored separately from other data:

  • Photos are uploaded to a private cloud storage bucket (Supabase Storage) under your user ID
  • Access is restricted by folder-based security — only your account can access your photos
  • Photos are automatically deleted after 14 days via a scheduled cleanup process
  • When you delete your account, all photos are immediately removed from cloud storage

Data Sharing

We do not sell your personal data. We share information only with the following service providers, solely as needed to operate the Service:

  • Supabase: Our database and authentication provider (if you enable cloud sync). Supabase stores your synced data and tongue photos on secure servers. Supabase processes data according to their privacy policy.
  • OpenAI: If you opt into AI tongue analysis, your tongue photo is sent to OpenAI's GPT-4o vision model for pattern analysis. The photo is processed in transit and not retained by OpenAI. OpenAI does not use API data to train their models. See OpenAI's privacy policy.
  • Apple: For HealthKit (step count, sleep, heart rate), WeatherKit (weather conditions), and Sign in with Apple integrations, subject to your permissions and Apple's privacy policy.
  • Vercel: Website hosting and analytics.

We may disclose information if required by law or to protect our legal rights.

Data Retention

Local data: Retained until you delete the app or clear app data. Signing out of your account clears all local data for privacy.

Cloud data: Retained until you delete your account. When you sign out, local data is cleared for privacy, but cloud data is preserved so you can sign back in later.

Tongue photos (cloud): Automatically deleted after 14 days. Only the reading metadata (observations, patterns, dates) is retained long-term.

Account deletion: When you delete your account (available in Settings), all cloud data is permanently removed — including your profile, daily logs, progress records, cabinet, program enrollments, tongue reading metadata, and tongue photos. This action cannot be undone.

Your Rights

You have the right to:

  • Access the personal data we hold about you
  • Correct inaccurate data through the app's editing features
  • Delete your account and all associated cloud data (Settings > Delete Account)
  • Export your data by contacting us
  • Withdraw consent for optional features (HealthKit, location, notifications, AI tongue analysis) at any time via iOS Settings or in-app Settings
  • Opt out of AI analysis and use manual tongue observation instead

To exercise these rights, contact us at support@terrainhealth.app.

Children's Privacy

Our Service is not directed to individuals under 13 years of age. We do not knowingly collect personal information from children. If you believe a child has provided us with personal information, please contact us.

Security

We implement appropriate technical and organizational measures to protect your personal information:

  • Row-level security on all database tables (only you can access your data)
  • Folder-based access control on photo storage (your photos are in your folder only)
  • Encrypted data transmission (HTTPS/TLS) for all network requests
  • Secure authentication via Supabase Auth (email + Apple Sign In)
  • JWT-validated server functions for sensitive operations (AI analysis, account deletion)

No method of transmission or storage is 100% secure. We cannot guarantee absolute security.

No Tracking or Advertising

Terrain does not use third-party advertising networks, tracking pixels, or behavioral analytics in the iOS app. We do not build advertising profiles or share data with advertisers. HealthKit data is never used for advertising, marketing, or use-based data mining.

Third-Party Services

Our Service integrates with:

  • Apple HealthKit: For optional step count, sleep analysis, and resting heart rate data
  • Apple WeatherKit: For location-based weather conditions (weather data provided by Apple Weather)
  • Apple Photo Library: For optional photo selection when using tongue diagnosis (requires your permission)
  • OpenAI GPT-4o: For optional AI-powered tongue photo analysis (requires explicit consent)
  • Supabase: For optional cloud sync, authentication, and photo storage
  • Vercel: Website hosting and analytics

Each of these services has their own privacy policies. We encourage you to review them.

Medical Disclaimer

Terrain is a wellness and lifestyle app inspired by Traditional Chinese Medicine (TCM) principles. It is not a medical device and does not provide medical advice, diagnoses, or treatment. The app's observations, patterns, and recommendations are for general wellness and educational purposes only. Always consult a qualified healthcare provider before making changes to your diet, exercise, or health routine.

International Users

Our servers are located in the United States. If you access the Service from outside the US, your information may be transferred to and processed in the US. By using the Service, you consent to this transfer.

Changes to This Policy

We may update this Privacy Policy from time to time. For material changes, we will notify you through the App or via email if you have an account. The updated policy will be posted here with a new revision date.

Contact

If you have questions about this Privacy Policy or your personal data, please contact us at support@terrainhealth.app.