Privacy Policy

Last updated: May 19, 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, AI-powered tongue analysis, HealthKit access, location access, and notifications are optional.

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, if you provide one)

Terrain Profile

When you take the terrain assessment quiz, we store:

  • Your quiz responses and calculated scores
  • Your terrain type and modifier
  • Your wellness goals
  • Optional demographics such as age, gender, and ethnicity for personalization

Safety Preferences

You may optionally disclose health-related information to help us filter content and show safety notes.

  • Pregnancy or breastfeeding status
  • Medication-related flags such as blood thinners, blood pressure, thyroid, or diabetes medication
  • Dietary considerations such as GERD, caffeine avoidance, or histamine intolerance

Daily Check-ins and Progress

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

  • Mood ratings
  • Symptom selections
  • Sleep, digestion, temperature-feeling, and related wellness check-in responses
  • Routine completions, feedback, streaks, and program progress

Tongue Reading Photos and Observations

The Tongue feature lets you photograph your tongue for a wellness reading inspired by Traditional Chinese Medicine observation principles. When you use this feature:

  • Photos are stored locally on your device in the app's private sandbox
  • With an account, photos may be uploaded to our cloud storage for cross-device sync
  • Cloud photos are automatically deleted after 14 days; observation metadata may remain with the reading history
  • Structured observations such as color, shape, coating, and moisture may be stored with each reading
  • Photos selected from your photo library are used only for the tongue-reading feature

AI-Powered Tongue Analysis (Optional, With Your Permission)

If you choose AI-powered tongue analysis, Terrain asks for your permission before sending data to a third-party AI service. When you opt in, Terrain sends the following data to our secure backend and then to OpenAI's GPT-4o model to generate the reading:

  • Your tongue photo
  • Your terrain type
  • Your terrain modifier

We use this information only to generate and return an AI-assisted tongue reading.

  • Who receives the data: Supabase (our backend infrastructure provider) and OpenAI (our AI model provider)
  • Why it is shared: To process your requested tongue analysis and return structured observations and wellness insights to the app
  • Retention: OpenAI does not train on API data by default; temporary safety or abuse-monitoring retention may apply under OpenAI's API terms
  • Your control: AI analysis is optional, requires your permission before use, and can be turned off in the app at any time
  • Stored results: If you save a reading, the resulting AI-generated observations, notes, and impression may be stored with that reading

OpenAI processes data according to their privacy policy.

Health Data (Optional, With Permission)

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

  • Step count
  • Sleep duration and in-bed time
  • Resting heart rate

HealthKit data is:

  • Read-only
  • Used to display trends and personalize wellness content
  • Stored locally and synced only if you create an account
  • Never used for advertising or sold to data brokers

Location and Weather (Optional, With Permission)

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

  • We do not store or transmit your precise location as part of your profile
  • Weather condition and temperature may be cached in your daily log to personalize content
  • The app continues to function if you decline location access

Notifications (Optional, With Permission)

With your permission, Terrain may send local reminders about your routines and check-ins.

Subscription and Purchase Information

If you subscribe to Terrain Pro, Apple processes your payment through StoreKit. We do not receive your full payment card details. We may receive and store limited subscription data such as:

  • Your subscription status
  • The plan you selected
  • Trial eligibility and purchase events needed to unlock premium features

Terrain also uses Superwall to help manage subscription state and paywall presentation.

App Analytics

Terrain uses Amplitude to understand app usage, improve reliability, and evaluate feature and subscription flows. Analytics may include app lifecycle events, feature interactions, product interaction events, device identifiers, and a user identifier when you are signed in.

  • Analytics are used for product improvement and app functionality, not advertising
  • We do not sell analytics data to data brokers
  • HealthKit data and tongue photos are not used for advertising

Website Visitors

When you visit our website, we may collect standard website analytics such as browser type, device type, pages visited, and referring URL via Vercel Analytics.

How We Use Your Information

We use the information we collect to:

  • Personalize your terrain-specific content, routines, ingredients, and suggestions
  • Display relevant safety notes
  • Track your progress and show wellness trends over time
  • Generate tongue reading interpretations and AI-assisted results when you request them
  • Sync your data across devices if you create an account
  • Support subscriptions and premium feature access
  • Understand app feature usage, reliability, and subscription funnel performance
  • Improve the Service and develop new features
  • Respond to support requests or feedback

Data Storage

Local-First Architecture

By default, your data is stored locally on your device using Apple's on-device storage frameworks.

  • Your data stays on your device unless you opt into cloud sync or AI analysis
  • The app works offline for core features
  • Uninstalling the app removes local app data from that device

Cloud Sync (Optional)

If you create an account, your data syncs to our cloud infrastructure hosted by Supabase.

  • Profile data
  • Daily logs and progress
  • Cabinet and program data
  • Tongue reading metadata and temporary cloud photo storage

Cloud-synced data is encrypted in transit and protected by account-level access controls.

Data Sharing

We do not sell your personal data. We share data only with service providers needed to operate the Service.

  • Supabase: Our authentication, database, and storage provider for optional cloud sync and AI request handling. See Supabase's privacy policy.
  • OpenAI: If you opt into AI tongue analysis, your tongue photo, terrain type, and terrain modifier are sent to OpenAI through our backend to generate the requested analysis. See OpenAI's privacy policy.
  • Apple: Apple processes in-app purchases through StoreKit and may provide HealthKit, WeatherKit, notifications, and Sign in with Apple services depending on what you enable.
  • Superwall: Used to help manage subscription state and paywall presentation.
  • Amplitude: Used for app analytics such as feature usage, app lifecycle events, product interaction events, and product improvement.
  • Vercel: Hosts our website and may process standard website analytics and infrastructure logs.

Your Choices

  • You can use the app without creating an account
  • You can disable AI tongue analysis and use manual observation instead
  • You can decline HealthKit, location, photo library, and notification permissions
  • You can delete your account from within the app

Children's Privacy

Terrain is not directed to children under 13, and we do not knowingly collect personal information from children under 13.

Changes to This Policy

We may update this Privacy Policy from time to time. When we do, we will revise the date at the top of this page.

Contact

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