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, and daily health logs, which can include basal body temperature, cervical mucus, sleep, exercise, water intake, weight, sexual activity, contraception method, free-text notes, pregnancy tracking (due date, symptoms, weight, blood pressure, kick and contraction sessions, appointment details you enter such as provider name and location), and perimenopause tracking (hot flashes, triggers, hormone test results). This data is entered by you and used solely to provide cycle tracking, predictions, and insights.
Apple Health (optional, iOS): If you enable “Import periods from Apple Health” in Settings, Crimson reads menstrual-flow data from Apple Health (including entries logged from an Apple Watch). If you enable Apple Health sync, Crimson also writes your logged menstrual flow, basal body temperature, and mappable symptoms to Apple Health, where they are governed by your Apple Health permissions and readable by other apps you have authorized. Both directions are separate opt-in toggles and can be disabled at any time.
Profile and subscription data: The display name you choose during onboarding, an optional birth date, your tracking goal and app mode, and — if you subscribe — your subscription tier, expiry, and the store transaction identifiers (Apple original transaction ID or Google Play purchase token) needed to validate and maintain your purchase.
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 typed messages and the AI's responses are processed to provide personalized cycle insights. Chat history is stored only on your device — it is not synced to our cloud — and is removed when you delete the app or clear its data.
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. Starting with Crimson 1.0.20, the health content the app keeps on your device, such as AI chat history, AI summaries, and logs waiting to sync, is excluded from iCloud and Google device backups. App settings such as reminders and theme may still be included in an iPhone backup.
Cloud sync: Synced data lives in our Convex-hosted cloud database in the United States, scoped to your account with server-side access controls so that requests can only read or write the records belonging to the signed-in account. Data is encrypted in transit (TLS 1.2+) and at rest. It is not end-to-end encrypted: like most cloud services, our systems can technically access stored data, and we do so only for the purposes in this policy (for example, operating the service and debugging with your cooperation).
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 processes this data under OpenRouter's privacy policy and forwards it to a model provider. Every request is routed through our server, which prepends safety rules, never attaches your identity, and instructs OpenRouter to use only providers whose policy is not to train on or retain prompts, and never Google. The specific provider varies by request within that rule. 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. If you fill in the feedback form on our website, your chosen answer, any text you type, and your email address if you choose to leave it are stored there as well.
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.
Brevo (email): When a subscription purchase is confirmed, our backend sends a one-line operational alert email to the developer through Brevo (Sendinblue SAS). The alert contains your account identifier and subscription dates — never your health data. When you submit the feedback form on our website, your answer (and your email address, if you chose to leave it) is also emailed to the team through Brevo so we can reply. We also occasionally send account-related email to you through Brevo from support@getcrimson.app — for example, a short note after you sign up asking how it went. Those emails contain your email address and first name, never your health data, we keep a record of which of these emails we have sent you so you never receive the same one twice, and you can stop them with the unsubscribe link in any of them, or by emailing support@getcrimson.app. Brevo processes this under Brevo's privacy policy.
Apple and Google (purchases): Subscriptions are billed by the Apple App Store or Google Play under their own terms. To validate purchases, our backend receives and stores the store's transaction identifiers and receives server-to-server subscription status notifications from Apple.
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 and Deletion
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 your cloud data at any time through the app's settings, or via the steps on our account deletion page.
What survives account deletion: to prevent repeated free trials, we retain a minimal fraud-prevention record consisting of your account identifier and the date your trial started — no health data, name, or email. Residual copies inside our infrastructure providers' encrypted backups expire on their normal rotation schedules. Crash reports already sent to Sentry (which never contain your identity or health data) age out under Sentry's retention. Purchase records held by Apple or Google are governed by those stores. Prompts already processed by AI model providers are subject to the retention described in the AI section above.
Health Data and Legal Requests
We treat menstrual and reproductive health data as highly sensitive. We do not voluntarily share it with any government agency, law-enforcement body, or private litigant. If we receive a subpoena, court order, or other legal demand, we will disclose data only where we conclude the demand is valid and legally binding, we will interpret it as narrowly as the law allows, and — where the law permits — we will notify you before disclosing. Because we retain only what this policy describes, much of what such demands typically seek (precise location, advertising identifiers, third-party trackers) simply does not exist in our systems.
Consumer Health Data (Washington, Nevada, and similar laws)
This policy, including this section, serves as our consumer health data privacy policy. The categories of consumer health data we collect and our purposes are described above (“Data We Collect” and “How We Use Your Data”); the third parties that process it are listed under “Third-Party Services”; we do not sell consumer health data or share it for advertising. You may withdraw consent (for example, revoking AI data sharing in Settings), access your data, and delete it as described in “Your Rights.” If we decline a request you make under a consumer health data law, you may appeal by replying to our decision email with the subject “Appeal”; we will respond within the period the applicable law requires, and you may also contact your state Attorney General.
California Privacy Rights
If you are a California resident: the categories of personal information we collect are identifiers (email, account ID), health information, and commercial information (subscription status); we collect them for the purposes above; and we do not sell or share personal information as those terms are defined in the CCPA/CPRA, nor use sensitive personal information for anything other than providing the service. You have the rights to know, delete, correct, and limit use of sensitive personal information, and to not be discriminated against for exercising them. Exercise any of these in the app (export, delete, AI-sharing toggle) or by emailing support@getcrimson.app.
European Users (GDPR, UK GDPR, Swiss FADP)
For users in the EEA, UK, or Switzerland: we process your health data on the basis of your explicit consent (Art. 9(2)(a) GDPR), given when you accept the in-app health terms and, separately, when you enable AI data sharing; account and session data are processed to perform our contract with you and on our legitimate interest in securing accounts. Your data is stored on servers in the United States; by using Crimson you understand your data is transferred to and processed in the US as described in this policy. In addition to the rights listed below, you may rectify inaccurate data (editable directly in the app), restrict or object to processing, receive your data in a portable format (CSV export), withdraw consent at any time without affecting prior processing, and lodge a complaint with your local supervisory authority.
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 (exports include everything you logged, including free-text notes — handle exported files with the same care as any medical record)
- Delete your account and all associated data
- Correct your data — every log and profile field is editable in the app
- Revoke AI data-sharing consent at any time in the app's Settings
- Appeal a refused request by emailing us with the subject “Appeal”
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.