Privacy Policy

Last updated: October 15, 2026

This Privacy Policy explains how Dayvil (“Dayvil”, “we”, “us”, or “our”) collects, uses, shares, and protects information when you use the Dayvil mobile app, website, and related services.

Dayvil is a visual day-tracking app. It can help you track routines, reminders, metrics, time-based actions, progress reports, and shared support contexts. Dayvil is not a medical device and does not provide medical, mental-health, legal, financial, or other professional advice.

Who is responsible (data controller)

The data controller responsible for processing your personal data is:

Email: hello [at] dayvil.com

For full provider details, including the postal address, see the Imprint.

1. Information we collect

  • Account information — anonymous account identifiers, Google or Apple sign-in identifiers, email address, display name, and profile information you choose to provide.
  • Dayvil content — actions, routines, schedules, reminders, day entries, metrics, reports, settings, sharing memberships, invites, and other content you create in the app.
  • Sharing information — names, roles, access levels, invite details, and activity needed to let you share a Dayvil with another person or access one shared with you.
  • Notification information — reminder settings and device notification tokens where needed to deliver notifications you enable.
  • Purchase and subscription information — subscription status, product identifiers, entitlement status, and related purchase metadata from Apple, Google, and RevenueCat. We do not receive your full payment card number.
  • Device, diagnostics, and usage information — app version, device type, operating system, crash reports, performance data, analytics events, ad-related events, and security logs.
  • Coach and AI-insight data — when you choose to use the optional Coach feature, we generate a summary of your recent logged activity and send it to our AI provider to produce insights. This summary can include values you have chosen to track that may be health-related (for example mood, sleep, weight, or similar). We process this only when you actively request an analysis. See AI-powered insights (Coach) below.
  • Support and website information — messages you send to us, email address, and basic website/server logs generated when you visit the Dayvil website.

2. How we use information

  • Provide, sync, and secure your Dayvil account and app data.
  • Show your Day Map, action history, reports, settings, and shared Dayvils.
  • Send reminders and notifications you choose to enable.
  • Support sharing, invitations, access controls, and context switching.
  • Process subscriptions, restore purchases, and manage paid features.
  • Show ads where applicable and hide ads for subscribed users.
  • Generate optional AI-powered insights about your routine when you use the Coach feature.
  • Understand app usage, diagnose crashes, prevent abuse, and improve Dayvil.
  • Respond to support requests and communicate important service or policy updates.

3. Sharing and visibility

We do not sell your personal information. We share information only as needed to operate Dayvil, comply with law, protect the service, or honor choices you make in the app.

When you invite someone to a Dayvil, that person may see the actions, routines, entries, reports, and context made available through that shared Dayvil. You are responsible for choosing what to share and with whom. Shared access can be changed or removed in the app where sharing controls are available.

You can also connect an AI agent or script of your own choosing to your Dayvil. A connected agent can read your actions, logged entries, and streaks, and — if you grant it write access — log entries on your behalf. The agent is chosen and operated by you, not by us: what it stores, remembers, or passes on is governed by its own provider's terms. We instruct connected agents not to forward your data to third parties and not to give medical advice, but we cannot enforce this. Every connected agent is listed in the app and you can revoke its access at any time; revocation takes effect within about a minute.

4. Service providers

Dayvil may use the following service providers to operate the app and website:

  • Google Firebase — authentication, database (Cloud Firestore), file storage, cloud functions, analytics (Google Analytics for Firebase), crash reporting (Firebase Crashlytics), messaging, device attestation (Firebase App Check, which verifies through Apple App Attest or Google Play Integrity that requests come from the genuine app — the attestation carries no personal data), and related infrastructure. Our database and cloud functions are located in Google data centres in the United States (see section 10).
  • Google Sign-In and Sign in with Apple — account sign-in and account linking.
  • RevenueCat — subscription entitlement management and purchase status.
  • Apple App Store and Google Play — app distribution, in-app purchases, subscriptions, refunds, and store account processing.
  • Google AdMob — advertising for users who do not have an ad-free subscription. In regions where consent is required (such as the EEA and UK), ads are personalized only if you consent; otherwise you see non-personalized ads.
  • Google (Gemini via Vertex AI) — AI processing to generate optional Coach insights and other AI suggestions from a summary of your activity. This processing takes place on Google Cloud servers located in the European Union. Your data is not used to serve ads or to train AI models.
  • Expo, Apple Push Notification service, and Firebase Cloud Messaging — app delivery tooling and notifications where used.
  • Hetzner Online GmbH (Germany) — hosts our own servers in the European Union for app updates, icon search, translation, the relay that forwards AI requests to Google, and the agent interface (mcp.dayvil.com) through which an AI agent you connect reads or writes your Dayvil. When the app checks for an update, uses one of these features, or a connected agent makes a request, your device's IP address and basic device and app-version information reach these servers; they are kept in access logs for up to 60 days.
  • Email providers — support messages sent to our support address.

AI-powered insights (Coach)

Coach is an optional, on-demand feature. It runs only when you tap to request an analysis. If you never use Coach, none of your data is sent for AI processing.

When you request an analysis, we send a summary of your recent logged activity to our AI provider (Google, via Vertex AI) to generate suggestions and observations about your routine. This processing happens on Google Cloud servers located in the European Union, and the results are shown only to you. We do not use this data to serve you ads or to train AI models.

Some values you choose to log (for example mood, sleep, or weight) may qualify as health-related data, which is a special category of personal data under the GDPR (Art. 9). We process such data for Coach only on the basis of your explicit consent (Art. 9(2)(a) GDPR), which we request the first time you use Coach. You can decline — in that case Coach stays off and no such data is sent — and you may withdraw consent at any time by not using the feature. Dayvil is not a medical device and Coach insights are not a medical assessment or professional advice.

Advertising and your choices

Dayvil shows ads to users who do not have an ad-free subscription. You can remove ads entirely by subscribing to a paid plan.

Where required (for example in the EEA and UK), we ask for your consent through Google's consent form before any personalized ads are shown and, on iOS, through Apple's App Tracking Transparency prompt. If you do not consent, you still see ads, but they are non-personalized. Where the GDPR applies, personalized advertising relies on your consent (Art. 6(1)(a) GDPR). You can review or change your tracking choice at any time in your device settings.

5. Website analytics and cookies

On the Dayvil website we use Google Analytics 4 to understand how visitors use the site (for example, which pages are viewed and roughly where visitors come from) so we can improve it. Google Analytics may set cookies and process limited usage data, such as a pseudonymous identifier, pages viewed, approximate location derived from your IP address (which we have configured to be anonymized), and basic device and browser information.

We load analytics with consent controls (Google Consent Mode). When you first visit the site we ask for your choice through a cookie banner. Until you accept, analytics runs without storing cookies on your device. If you accept, analytics cookies are enabled; if you reject, they remain disabled. You can change your choice at any time by clearing the site’s stored settings in your browser, which makes the banner appear again. Where the GDPR applies, we rely on your consent (Art. 6(1)(a) GDPR) for analytics cookies.

6. Legal bases for processing

Where privacy laws such as the GDPR apply, we process information based on one or more of the following legal bases: providing the service you request, your consent, our legitimate interests in operating and improving Dayvil, compliance with legal obligations, and protecting users and the service from misuse.

7. Data retention and deletion

We keep your account content for as long as your account exists. You can delete your account in the app (Profile → Advanced → Delete account) or by contacting us; deletion removes your account data from our live systems immediately. The following retention periods apply:

  • Account content (actions, day entries, metrics, reports, Coach analyses, settings, sharing memberships, consent records) — until you delete your account.
  • Backups — residual copies are overwritten within 30 days of deletion.
  • Anonymous accounts that have not been used for 12 months may be deleted together with their data.
  • Crash reports — 90 days. Analytics events — up to 14 months.
  • Server access logs (IP address, request time, route) — up to 60 days.
  • Purchase and subscription records held by Apple, Google, and RevenueCat, and records we must keep for tax or accounting reasons — for the period required by law (in Austria generally 7 years).

8. Your choices and rights

  • You can use Dayvil anonymously where the app allows it.
  • You can link an anonymous account to Google or Apple to keep access across devices.
  • You can disable reminders and notification permissions in your device settings.
  • You can manage subscriptions through Apple App Store or Google Play account settings.
  • You can request access, correction, export, restriction, objection, or deletion of your personal information by contacting us.
  • Where processing is based on your consent (Coach, AI suggestions, photo scan, personalized ads), you can withdraw that consent at any time in the app's Settings, with effect for the future.
  • You have the right to lodge a complaint with a data protection supervisory authority. For Dayvil the competent authority is the Austrian Data Protection Authority: Österreichische Datenschutzbehörde, Barichgasse 40–42, 1030 Vienna, Austria, www.dsb.gv.at, dsb@dsb.gv.at. You may also contact the authority of your own EU member state.

9. Security

We use technical and organizational measures designed to protect your information, including authenticated access, role-based sharing controls, and managed cloud infrastructure. No method of transmission or storage is perfectly secure, so we cannot guarantee absolute security.

10. International transfers

Some of our service providers process your information outside the European Economic Area, in particular in the United States: Google (Firebase database, storage, cloud functions, analytics, crash reporting, messaging), Apple and Google as app-store operators, RevenueCat (subscription status), and Expo (push-notification delivery). For these transfers we rely on the EU–US Data Privacy Framework where the provider is certified under it, and otherwise on the European Commission's Standard Contractual Clauses together with the provider's data processing terms. Our own servers (Hetzner) and the AI processing described above are located in the European Union.

11. Children’s privacy

Dayvil is not directed to children. You must be at least 16 years old to use Dayvil yourself; we do not knowingly collect personal information from anyone younger. Adults may use Dayvil to support a child’s routine, but the adult is the account holder and is responsible for what is entered and shared. If you believe a child under 16 has created an account, please contact us and we will delete it.

12. Changes to this policy

We may update this Privacy Policy as Dayvil changes. When we do, we will update the “Last updated” date above and, where appropriate, provide additional notice in the app or on the website.

13. Contact

Questions or requests about privacy can be sent to Dayvil feedback.