Last updated: 23 July 2026

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1. Who we are

Moon Quest is a cycle-aware companion app for people who experience PMS, PMDD, or premenstrual exacerbation of existing conditions. Moon Quest is operated by Helene Choo, trading as Moon Quest, a sole proprietorship (eenmanszaak) registered in the Netherlands. For the purposes of the EU General Data Protection Regulation (GDPR) and the UK GDPR, Moon Quest is the controller of the personal data described in this Privacy Policy.

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You can contact us about anything in this policy at:

• Email: privacy@moonquest.app or contact@moonquest.app

• Post: Moon Quest, De Duinsloot 46, 2211 DS Noordwijkerhout, Netherlands

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This Privacy Policy covers the Moon Quest mobile application and the backend services that support it, including authentication, subscription validation, and optional cloud sync. Purchases made through our journal shop at moonquest.shop are covered by the separate privacy notice published there. This policy also does not govern services that act as independent controllers, such as Apple and Google, except where we describe how they interact with Moon Quest.

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2. Our approach to your data

Information about menstrual cycles, symptoms, and mood is sensitive. In most cases it qualifies as special category health data under Article 9 of the GDPR and UK GDPR, and we treat it that way regardless of edge cases.

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Our approach rests on four commitments:

• Local first. The app is designed to work fully on your device without an account. If you never sign in, your period logs, mood logs, and predictions stay on your phone and are not transmitted to our servers.

• No advertising. We do not show advertisements, we do not use advertising trackers or advertising SDKs in the app, and we never use your data, health-related or otherwise, for targeted advertising.

• No selling or sharing for commercial gain. We do not sell personal data and we do not share it with data brokers, advertisers, or research partners.

• Minimal collection. We collect only what is needed to run the app and its optional cloud features.

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Moon Quest is not a medical device and does not provide diagnosis or treatment.

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3. Data we process

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3.1 Health and Cycle Data

This is the most sensitive category of data we process. It consists of the information you choose to enter in the app, including:

• period log dates;

• cycle settings, such as your average cycle length and average period length;

• daily symptom and mood check-in values for the seven metrics used in the app: mood swings (lability), irritability, depressed mood, anxiety, feeling overwhelmed, fatigue, and interference;

• predicted values and derived scores generated on your device, including the Emotional Load Index (ELI);

• insight completion records for the in-app learning content.

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We process this data on the basis of your explicit consent, which you give during onboarding. If you do not sign in, this data is stored only on your device.

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3.2 Account and Identity Data

If you choose to sign in to enable cloud features, we process account-related data such as your Moon Quest user ID, display name, email address, whether your email address has been verified, your profile image where provided by your sign-in provider, and authentication provider information associated with your account. Moon Quest supports optional sign-in through Apple and Google. The app can be used without creating an account.

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3.3 Authentication and Session Data

To maintain signed-in sessions and protect account security, we process session identifiers and tokens, session expiry timestamps, IP address and user-agent information associated with authenticated sessions, and the authentication references required by the sign-in system. On your device, authentication credentials are stored using the platform's secure storage.

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3.4 Subscription and Purchase Data

Moon Quest offers a free tier and an optional paid subscription that unlocks additional features. To operate subscriptions and verify entitlements, we process RevenueCat anonymous user identifiers, Moon Quest user IDs linked to subscription status when you sign in, subscription and entitlement status, expiration dates, product identifiers, store metadata, and limited subscription event metadata. When you sign in, we may set your email address in RevenueCat for account reconciliation.

We do not store your payment card details. Payments made through the Apple App Store or Google Play are handled by those platforms as independent controllers of your payment data.

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3.5 Local App State

Because Moon Quest is local first, the app stores state on your device, including your onboarding progress, consent status, whether introductory screens have been seen, a locally stored display name entered during onboarding, and locally cached content. This data lives in app storage or a local SQLite database on your device and supports offline use.

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3.6 Usage, Device, and Diagnostic Data

After you complete the onboarding consent flow, we collect product analytics through PostHog, hosted in the European Union. This includes app lifecycle events, screen navigation events, app version and device environment metadata, and crash and error information. Our analytics are configured to exclude health data: cycle length and period length values are filtered out at ingestion and are not stored in analytics, and Geo-IP location lookup is disabled.

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For backend services, we process technical request metadata such as request path and method, and IP address or related network metadata where processed by our hosting, analytics, authentication, or infrastructure providers for routing, security, or diagnostics.

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We do not use analytics to collect the contents of your period logs or daily symptom entries.

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4. Why we process your data, and on what legal basis

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We process personal data for the following purposes:

• To provide the core app experience: recording your logs and settings, calculating cycle context and derived scores, generating on-device predictions, and preserving your progress between sessions. Legal basis: Article 6(1)(b) (performance of a contract) and, for health data, Article 9(2)(a) (your explicit consent).

• To enable optional accounts and cloud sync: authenticating you, associating synced records with your account, syncing changes between devices, and propagating deletions. Legal basis: Article 6(1)(b) and, for synced health data, Article 9(2)(a). The data types synced when you are signed in are period logs, cycle settings, mood logs, avatar configuration, gamification state, insight completion records, and the deletion markers needed to propagate deletions.

• To manage subscriptions and access control: determining whether a subscription is active, reconciling purchases, and enabling or disabling subscription-gated features. Legal basis: Article 6(1)(b).

• To authenticate via Apple or Google when you choose social sign-in. Legal basis: Article 6(1)(b).

• To analyse, maintain, secure, and improve the app: consent-based product analytics, crash diagnostics, and infrastructure security. Legal basis: Article 6(1)(a) (consent) for in-app analytics; Article 6(1)(f) (legitimate interests) for security, abuse prevention, and service integrity; Article 6(1)(c) where we must comply with applicable law.

• To respond to your requests and handle legal matters: answering enquiries, handling data subject requests, and establishing, exercising, or defending legal claims. Legal basis: Articles 6(1)(b), 6(1)(c), and 6(1)(f) as applicable, and Article 9(2)(f) where special category data is relevant to legal claims.

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Where processing is based on consent, you can withdraw consent at any time by contacting us at privacy@moonquest.app. Withdrawal does not affect the lawfulness of processing carried out before it. Because Moon Quest's core functionality depends on processing the data you enter, withdrawing consent for that processing may mean some or all features stop being available to you.

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5. Third parties we use

We use a small number of service providers to run Moon Quest. Where they process personal data on our behalf, they act as processors under a data processing agreement. None of them receive your data for their own advertising or commercial purposes.

• Vercel (backend hosting). Hosts our backend services in the European Union (Frankfurt, Germany), and processes infrastructure and request-related data such as network metadata, IP addresses, and request logs needed to host and secure the backend. Vercel relies on the EU Standard Contractual Clauses, the UK Addendum, and is certified under the EU-U.S. Data Privacy Framework.

• Neon (database hosting). Hosts the PostgreSQL database used for authentication, subscription records, and optional synced user records, in the European Union (Frankfurt, Germany). Where personal data is stored in Neon, Neon acts as a processor on our behalf under a GDPR-aligned data processing agreement, with encryption in transit and at rest.

• PostHog Cloud EU (product analytics and diagnostics). Processes consent-based in-app analytics and backend exception reporting. Our PostHog workspace is hosted in the European Union and Geo-IP lookup is disabled.

• RevenueCat (subscription infrastructure). Processes subscription identifiers and entitlement metadata, and your email address where we provide it after sign-in. RevenueCat acts as a processor and provides a data processing addendum.

• Apple and Google (sign-in, app stores, and billing). Independent controllers when you sign in with their services or purchase through their stores. We receive limited account information from them when you use their sign-in services; we do not control how they process data for their own platform purposes.

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We do not share personal data with any third party not listed here, except where required by law or as described in this policy. If we add or change a provider that processes personal data, we will update this policy.

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6. Where your data is stored, and international transfers​

If you use Moon Quest without signing in, your health and cycle data is stored only on your device and is not transferred anywhere.

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If you sign in, synced data and account data are stored in our backend database and hosting infrastructure, which is located in Frankfurt, Germany. Our analytics (PostHog) are also hosted in the European Union. Your health and account data is therefore stored within the European Union and protected by EU data protection law.

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Where personal data is transferred outside the European Economic Area, the United Kingdom, or Switzerland, we rely on appropriate safeguards under applicable law, including the European Commission's Standard Contractual Clauses, the UK Addendum, and, where a provider is certified, the EU-U.S. Data Privacy Framework. You can request further details about these safeguards by contacting privacy@moonquest.app.

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7. Government and legal requests

We know that for many of our users, the question that matters most is not what we collect but who could ever demand it.

 

Our position:

• If you have never signed in, we hold no copy of your health data. There is nothing on our servers for anyone to request.

• We have never received a request from a government or law enforcement body for user data. If we ever do, we will disclose data only where we are subject to a legally valid and binding obligation, we will interpret any such obligation as narrowly as the law allows, and we will challenge requests that we believe are overbroad or lack a proper legal basis.

• Where the law permits, we will notify affected users before disclosing their data.

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8. Your rights

If you are in the EEA, UK, Switzerland, or another jurisdiction with similar protections, you have the right to request access to your personal data, correction of inaccurate data, deletion, restriction of processing, and portability of data you provided to us; to object to processing based on legitimate interests; to withdraw consent at any time where processing is based on consent; and to complain to a supervisory authority. In the Netherlands this is the Autoriteit Persoonsgegevens; in the UK, the Information Commissioner's Office.

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You can exercise these rights by contacting privacy@moonquest.app. You can delete your account and synced data from within the app's settings, or by contacting us. Deleting the app from your device removes all locally stored data.

We will need to verify your identity before acting on a request, and we will respond within the timelines required by applicable law. Moon Quest does not engage in automated decision-making that produces legal or similarly significant effects.

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9. Security

We use a combination of architectural, technical, and contractual measures to protect your data, including local-first storage so the app can operate without cloud transfer, platform secure storage for authentication credentials, authenticated backend routes for account-linked operations, TLS encryption for all data transmitted between the app and our backend, encryption at rest for hosted backend data, and data processing agreements with our providers.

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No system can guarantee absolute security. We recommend protecting your device with a passcode, Face ID, Touch ID, or the Android equivalent, and keeping your operating system up to date.

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10. How long we keep your data

• Local app data remains on your device until you delete it, reset the app, or uninstall the app.

• Synced health data and account data are deleted when you delete your account, subject to a short technical window for backup cycling. Where immediate deletion from backups is not possible, we isolate the data and delete it in the ordinary backup lifecycle.

• Subscription and financial records are retained for seven years where required by Dutch tax and administrative law, even after account deletion. These records do not include your health data.

• Session records expire automatically on a rolling basis.

• Analytics data is retained according to the retention settings of our analytics processor and is not linked to your health logs.

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11. Age

Moon Quest is intended for users aged 16 and over. We do not knowingly collect personal data from anyone under 16. If you believe a child under 16 has provided us with personal data, please contact us at privacy@moonquest.app so we can investigate and delete the data where appropriate.

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12. Changes to this policy

We may update this Privacy Policy to reflect changes in the app, the law, or our providers. The date at the top of this document shows when it was last revised. If we make a material change, particularly one affecting how health data is processed, we will notify users through the app or another appropriate mechanism before the change takes effect.

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13. Governing Language

If this Privacy Policy is translated into a language other than English, the English version governs in the event of a conflict, unless mandatory local law requires otherwise.