STELO Privacy Policy
Effective date: October 3, 2026
STELO is an iPhone app by Seokyoung You, operating as Quartz Labs ("we", "us"). This policy explains how information is handled in the app and when you use its support pages. Contact us at skyu.dev@gmail.com for privacy questions or requests.
At a glance
- Your activity modes and app selections are stored on your device. We do not upload your Screen Time reports or selected app lists to our servers or RevenueCat.
- STELO does not require an account. It has no advertising SDK and does not sell personal information or share it for cross-app targeted advertising.
- Purchases use Apple and RevenueCat. Purchase-related information is processed outside your device, including when the app checks your Pro access.
- Information you send in a support request is used to respond to you. Please leave out sensitive information that is not needed for your request.
1. Information stored on your device
STELO stores your selected activity, each mode's app access settings and ordering, always-allowed app selections, language, haptic preferences, and related display preferences.
The app also saves onboarding progress, draft app rules, and answers used to suggest an initial setup. To limit review prompts, it keeps local records such as the first-use date, qualifying usage days, and the dates and app versions for previous prompt attempts. These records are not sent to an analytics service. STELO does not record the star rating you choose or whether you submit a review.
App selections use identifiers provided by Apple's Screen Time frameworks. These identifiers are not a copy of the contents of the selected apps. STELO and its own extensions share the settings needed to apply restrictions, display the current mode, and support widgets and controls through a local shared container (an Apple App Group).
STELO does not provide its own cloud account or settings-sync service. Depending on your Apple device and backup settings, local app data may be included in backups managed by Apple. A restored backup may restore that data.
2. Screen Time permission and activity reports
With your permission, STELO uses Apple's Family Controls, Managed Settings, and Device Activity frameworks to let you select apps, apply a system blocking screen, and display recent activity reports. The report extension processes the activity information that iOS supplies to show app usage on your device. STELO does not transmit that report data to Quartz Labs, RevenueCat, or an advertising service.
STELO does not read your messages, photos, contacts, passwords, or the content inside other apps. Selecting an app such as Messages or Health for an access rule does not grant STELO access to that app's contents. STELO does not request location, microphone, camera, or advertising-tracking permission.
You can end a mode to remove restrictions applied by STELO. You can also revoke STELO's Screen Time authorization in iOS settings. Revocation does not cancel a paid subscription and does not necessarily erase preferences already stored locally. Rules imposed separately by iOS, another app, or a device administrator remain separate.
3. Purchases and Pro access
Apple handles App Store payments. We do not receive your payment card number. STELO uses RevenueCat to validate purchases, restore eligible purchases, determine Pro access, and understand subscription performance.
RevenueCat processes an automatically generated app user identifier, purchase and transaction history, product identifiers, subscription status, and associated app, platform, locale, and currency information. It may receive your IP address when the SDK connects to its service. STELO does not attach your email, Screen Time reports, or selected app lists to that identifier. This identifier is pseudonymous; it should not be understood as a guarantee that purchase data cannot be linked to a person.
The SDK is initialized when the app starts and can contact RevenueCat before you make a purchase, for example to check existing access. Apple retains purchase records under its own policies. More information: Apple Privacy Policy and RevenueCat Privacy Policy.
4. Support, website visits, and diagnostics
When you email us or use the website's contact form, we receive the contact details, message, and any attachments or device details you choose to send. We use them to investigate the request, respond, and maintain a support record. Do not send passwords, payment card details, or complete private app-usage histories.
Opening a website from STELO is a separate browser visit. The website's hosting and delivery services receive information needed to serve the page, such as an IP address, requested URL, browser information, and access time. Quartz Labs pages may also load Google Analytics when enabled in the site's configuration; this can process page visits, browser/device information, and cookie identifiers for website measurement. This is distinct from in-app Screen Time reporting. Browser privacy controls and content blockers can limit website tracking. See Google's explanation of data from partner sites.
STELO has no separate general-purpose in-app analytics or crash-reporting SDK in its current implementation. Apple may provide developer analytics or crash reports according to your Apple sharing settings and its policies. If you send a diagnostic report yourself, it is treated as support information.
5. Why we process information and who receives it
We process information to provide the features you request, validate and restore purchases, answer support requests, prevent abuse, understand purchase performance, and meet legal obligations. Where applicable, the legal grounds are performing our agreement with you, legitimate interests in operating and protecting the service, legal obligations, or consent where required. Screen Time access depends on your permission.
Information leaves your device only for the purposes described here. Recipients can include Apple, RevenueCat, website hosting and analytics providers, and email/support providers. We do not provide them your Screen Time selections or reports. We may disclose information if legally required or necessary to protect rights and safety. A business transfer may involve relevant records subject to applicable law and this policy.
Providers may process information outside your country, including in the United States. Applicable contractual and legal safeguards govern those transfers. You can contact us for information about the providers and safeguards relevant to your request.
6. Retention and deletion
Local preferences remain until changed or removed with the app's local data. Deleting STELO generally removes its local app data, but device backups and system-managed records may persist under Apple's controls. Local app deletion does not delete Apple or RevenueCat purchase records and does not cancel subscriptions.
We retain purchase-related information while necessary to provide and restore access, handle billing issues, prevent fraud, and satisfy applicable recordkeeping requirements. Support correspondence is retained as needed to resolve and follow up on the request or meet legal obligations; it is not a mailing-list subscription. We review requests for deletion and remove information no longer needed, subject to legally required retention and limited backup retention.
To request access, correction, or deletion, email skyu.dev@gmail.com with the subject STELO privacy request. We may ask for limited information to verify the request and locate a purchase record. We cannot remotely retrieve or delete local Screen Time selections we never received. Deleting a record may affect purchase restoration; we will explain the relevant consequences before acting. Cancellation of future charges is handled separately through Apple.
7. Your choices and rights
Depending on where you live, you may have rights to access, correct, delete, or obtain a copy of personal information, restrict or object to processing, withdraw consent, or complain to your local privacy authority. Contact us to exercise these rights. We will respond within applicable legal time limits and explain any exception that prevents fulfilling a request.
You can change app preferences, revoke Screen Time access, manage your browser's cookies and privacy controls, and manage subscriptions with Apple. Withdrawing Screen Time permission prevents permission-dependent features from working; it does not undo processing already lawfully performed.
8. Children
STELO is designed for people managing their own app use. It is not directed to children under 13, and we do not knowingly collect their personal information. Where local law requires a higher age or parental authorization, that requirement applies. If you believe a child has provided personal information, contact us so we can investigate and take appropriate action.
9. Security and policy changes
We limit collection to the purposes above and rely on iOS protections and encrypted connections for supported service communications. No storage or transmission method can be guaranteed completely secure.
We may update this policy as STELO changes. The effective date above identifies the current version. We will provide additional notice or obtain consent when required for a material change; posting an update does not replace consent where the law requires it.
10. Contact
Seokyoung You 路 Quartz Labs