Overview
Crimson, operated by Driftline Ventures LLC ("we", "our", "the company"), is an AI-powered period and fertility tracking application. Driftline Ventures LLC is the data controller for the information described in this policy. We are committed to protecting your privacy, especially given the sensitive nature of menstrual and reproductive health data. This policy explains what data we collect, how we use it, and your rights.
Data We Collect
Health data you provide: Period start/end dates, cycle lengths, symptoms, moods, daily health logs, and fertility-related information. This data is entered by you and used solely to provide cycle tracking, predictions, and insights. If you enable “Import periods from Apple Health” in Settings, Crimson also reads menstrual-flow data from Apple Health (including entries logged from an Apple Watch); imports stay in your account and the import can be disabled at any time.
Account information: Crimson requires a free account to use the app. Sign-in is handled by Clerk, which stores your email address and manages your login credentials. Your account enables secure cloud sync so your data is backed up and accessible across your devices.
AI chat interactions: If you use the AI assistant feature, your messages and the AI's responses are processed to provide personalized cycle insights. Chat history may be stored locally or in the cloud through your account.
Technical and session data: When you sign in, our authentication provider records your IP address, the approximate location derived from that address (city and country level only), and basic device details such as device type and app version. This is collected automatically each time a session is created or refreshed. We use it to keep your account secure, detect suspicious sign-ins, and let you see where your account is signed in. This is approximate, network-derived location — the app never requests permission to use your device's location services and never collects GPS coordinates. Where the GDPR or Swiss FADP applies, we process this data on the basis of our legitimate interest in securing user accounts.
How Your Data Is Stored
Local-first: Your health data is stored on your device using local storage, so the app stays fast and works offline. It is also synced to the cloud through your account for backup.
Cloud sync: Synced data lives in our Convex-hosted cloud database, scoped to your account so only you can access your records. Data is encrypted in transit (TLS 1.2+) and at rest.
How We Use Your Data
We use your data exclusively to:
- Display your cycle history and calendar
- Calculate cycle predictions and fertile windows
- Generate personalized AI insights based on your cycle phase and symptoms
- Sync your data across your devices
- Keep your account secure, detect suspicious sign-ins, and prevent fraud
We do not:
- Sell your data to third parties
- Share your health data with advertisers
- Use your data for purposes unrelated to the app's functionality
- Build advertising profiles from your health information
Third-Party Services
OpenRouter (AI features): If you explicitly agree in the app, the Crimson AI features send the following to OpenRouter, a third-party AI provider, to generate responses: your chat messages and a limited context built from your logs — your current cycle phase and cycle day, recent symptoms and moods from the last 7 logged days, hot-flash details if you track perimenopause, and your pregnancy week if you are pregnant. Your name, email address, and account identifiers are never included in AI requests. OpenRouter and the underlying model providers process this data under OpenRouter's privacy policy, which provides protections equal to those described in this policy; note that zero-cost AI models may retain prompts, so non-retention cannot be guaranteed. AI answers are educational content, not medical advice. You can grant or revoke this consent at any time in the app's Settings under "AI data sharing"; when revoked, no health data is sent to any AI service.
Convex (cloud sync): Your synced cycle data is stored in Convex's infrastructure, scoped to your account with server-side access controls, encrypted in transit (TLS 1.2+) and at rest. As the provider hosting our backend, Convex also processes the network-level connection data inherent in serving any internet request, including your IP address. We do not store your IP address in our own database.
Clerk (authentication): Account sign-in is handled by Clerk (Clerk, Inc.), which stores your email address and manages your login credentials to secure access to your data. Clerk also automatically records session metadata each time you sign in or your session refreshes: your IP address, the approximate location it resolves to (city and country), and device details such as device type and app version. This is used for account security and fraud prevention, and is retained by Clerk as part of your session history. Clerk never receives your health data. Clerk processes this data under Clerk's privacy policy.
Sentry (crash reporting): Release builds of the app send crash and error reports to Sentry (Functional Software, Inc.) so we can find and fix bugs. Reports contain technical details about the error and device (model, OS version, app version) — never your name, email, account identifiers, or health data. Crash reporting is disabled in debug builds. Sentry processes this data under Sentry's privacy policy.
Data Retention
Local data remains on your device until you delete the app or clear app data. Cloud-synced data is retained as long as your account is active. You can delete your account and all associated cloud data at any time through the app's settings.
Your Rights
You have the right to:
- Access all data we store about you
- Export your data as CSV or PDF reports at any time
- Delete your account and all associated data
- Revoke AI data-sharing consent at any time in the app's Settings
Children's Privacy
Crimson is not directed at children under 13. We do not knowingly collect personal information from children under 13. If you believe a child has provided us with personal information, please contact us and we will delete it.
Changes to This Policy
We may update this privacy policy from time to time. We will notify you of any material changes through the app or by updating the "Last updated" date above.
Contact Us
If you have questions about this privacy policy or your data, contact us at support@getcrimson.app.