Privacy Policy

1. Data controller and contact

One Line is published by KZ-apps. For privacy questions, requests, or concerns, contact us at support@oneline-app.com.

2. Data we collect

Depending on how you use One Line, we may collect:

• Content you create in the app, including daily lines, your first intro line, generated chapters, and content you choose to share.
• Personalization information provided during onboarding or in settings, such as your first name, situation, loved ones, pets, place of living, job, origin, interests, and narration preferences.
• A compact private narrative memory associated with your account, used to keep continuity between chapters. This memory is generated and updated server-side based on information you provide.
• Account information, such as your anonymous Firebase identifier, Google or Apple accounts you choose to link or restore, and metadata needed for backup or account switching.
• Contact information, such as your email address, when you contact support or request data deletion.
• Subscription and purchase-related information provided by Apple App Store, Google Play, and RevenueCat, such as product identifiers, subscription status, renewal state, transaction identifiers, and store receipts or purchase tokens needed to validate access. We do not receive or store your full payment card details.
• Technical information needed to operate, secure, debug, and improve the app, such as device type, operating system version, app version, crash logs, diagnostics, and performance data.
• Support messages and related metadata if you contact us.

3. Local data and cloud data

One Line uses local storage on your device for certain preferences and usage data, including language, consents, onboarding state, current week lines, generation day, daily reminders, and weeks already generated.

The app also uses Firebase for authentication and cloud storage. Main data may be stored in Firestore under your user identifier, including your profile, chapters, subscription status, generation usage, and private narrative memory.

When you restore or switch accounts, One Line clears local data tied to the previous account to avoid mixing lines, onboarding, or reminders from two accounts.

4. How we use your data

We use data only for the purposes needed to provide and improve One Line:

• Provide the core journal, personalized introduction, weekly chapter, history, sharing, and reminder features.
• Personalize the tone, point of view, and continuity of your story based on information you provide.
• Generate introductions and chapters from your lines, onboarding, narration preferences, and private narrative memory.
• Create, link, restore, or switch accounts through Firebase Auth, Google, or Apple when you choose to use those options.
• Validate in-app purchases, synchronize premium status, and manage access to paid subscription features through RevenueCat, the App Store, and Google Play.
• Apply generation quotas, prevent abuse, protect the service, and verify backend calls with Firebase App Check.
• Respond to support, privacy, and deletion requests.
• Maintain security, fix bugs, and improve reliability and performance.
• Comply with legal, accounting, tax, and platform obligations.

5. AI-generated content

One Line uses automated systems or artificial intelligence features to transform your daily lines and personalization information into an introduction or weekly chapter. Generation processing is performed server-side to protect technical secrets, apply quotas, and secure generation logic.

Generated chapters are based on the content you provide and may be imperfect, inaccurate, incomplete, or emotionally inappropriate. You should review generated content before relying on it or sharing it.

One Line aims not to invent life events or relationships that you did not provide, but no automated system can guarantee perfect accuracy.

6. Accounts, backup, and deletion

One Line can be used with anonymous Firebase authentication by default. You may choose to secure or restore your history with Google or Apple when those options are available in the app.

From the app settings, you can link an account, recover an already linked account, switch accounts, or request deletion of your cloud data. Switching accounts does not automatically delete cloud data from the account you leave.

Full cloud data deletion deletes data associated with your One Line account in Firebase when the operation is available and succeeds. This deletion does not automatically cancel an active App Store or Google Play subscription.

7. In-app purchases and subscriptions

One Line may offer paid features through auto-renewable subscriptions or other in-app purchases on iOS and Android. Purchases are processed by Apple through the App Store or by Google through Google Play, depending on your device and where you subscribed.

RevenueCat helps us validate purchases, restore entitlements, and synchronize premium status with the backend. We receive only the purchase and subscription information required to provide paid features.

You can manage or cancel subscriptions through your Apple Account subscriptions settings or Google Play subscriptions settings. Refund requests are handled by Apple or Google according to their applicable policies.

8. Legal bases for processing

Where applicable law requires a legal basis, we process your data to perform our contract with you, with your consent, to comply with legal obligations, and for legitimate interests such as security, fraud prevention, support, and service improvement.

9. Analytics and diagnostics

One Line uses Firebase Analytics to understand product usage, onboarding, conversion, paywall interactions, and other product events only when the applicable legal basis or consent allows it.

In countries covered by GDPR-like requirements, including the EU/EEA, the United Kingdom, and Switzerland, you can choose whether to allow product analytics from inside the app. Outside those countries, product analytics may be enabled by default if no choice has been recorded, but you can disable it at any time in the app privacy preferences.

Product analytics may include app interactions, onboarding progress, screen views, paywall interactions, purchase-related events without full payment details, app version, and device or platform technical information.

One Line also uses Firebase Crashlytics for diagnostics and stability. Crash reports may include crash logs, stack traces, app and device technical information, the screen or context of the crash when available, and a sanitized error type. Crashlytics is not intended to collect the personal journal content you write in the app.

Firebase Analytics and Firebase Crashlytics are services provided by Google/Firebase.

10. Your choices

You can manage privacy preferences at any time in the app privacy preferences.

From there, you can enable or disable product analytics and crash reports separately. Changes apply going forward and do not automatically delete data that may already have been processed before the change.

You can also manage daily reminders from the app and delete the app or its local data from your device.

11. Data storage and service providers

Your content may be stored locally on your device and may also be stored using cloud infrastructure providers when backup, history, generation, subscription, support, or diagnostics features are used.

We may share limited data with trusted service providers that help us operate One Line, including Firebase/Google Cloud, Vertex AI or an equivalent AI processing provider, RevenueCat, Apple, Google Play, analytics or crash reporting tools, and support tools. These providers may process data only as needed to provide their services to us.

12. Data sharing

We do not sell your personal data. We do not share your personal data for third-party advertising.

We may disclose data if required by law, to protect rights and security, to prevent abuse, or as part of a business transfer such as a merger, acquisition, or reorganization.

13. Data retention

We retain personal data only as long as necessary to provide One Line, maintain security, resolve disputes, comply with legal obligations, and support legitimate business needs.

Current week lines and certain preferences may be stored locally and deleted when you delete the app or device data. Cloud-stored data, such as your profile, chapters, private narrative memory, generation usage, and support messages, may remain until deletion is requested or retention is no longer necessary.

14. Your rights and deletion requests

Depending on your location, you may have rights to access, correct, export, object to, restrict, or delete personal data. You may request deletion of personal data associated with your account or support messages by contacting support@oneline-app.com or through the options available in the app.

Deleting app data does not automatically cancel an active App Store or Google Play subscription. You must cancel subscriptions through Apple or Google subscription settings.

15. Security

We use reasonable technical and organizational measures to protect your data, including Firebase authentication, Firestore rules, Firebase App Check for backend calls, and a separation between client-editable data and certain private fields updated server-side. However, no method of transmission or storage is completely secure, and we cannot guarantee absolute security.

16. Children

One Line is not intended for children under 13 or under the minimum age required by applicable law in their country. We do not knowingly collect personal data from children below that age.

17. International transfers

Your data may be processed in countries other than your country of residence. Where required, we use appropriate safeguards for international transfers.

18. Changes to this policy

We may update this Privacy Policy from time to time. The latest version will be available on this page, and the date above will reflect the latest update.

19. Contact

For privacy-related questions, contact us at:

support@oneline-app.com