Last updated: 02-09-2026
MONO ("the app") is developed and operated by Yuri van der Putten (Goudboom Enterprise), an independent developer based in the Netherlands. Contact details are at the bottom of this page.
MONO works without an account. We do not collect, transmit or sell any personal data. We operate no server. The app contains no analytics, no crash reporting and no third-party tracking. Your settings stay on your device. The only third-party processing happens through Google Play when you make a purchase.
The app requests these permissions solely to enable core features:
Display over other apps — required to draw the colour filter overlay across your screen. Without this the app cannot function.
Run in the background — keeps the filter active while you use other apps.
Notifications — Android requires apps running a background service to show a persistent notification while the filter is on. We send no marketing or promotional notifications.
Usage access (optional) — used to detect when an app you have excluded is in the foreground, so the filter can be hidden automatically. This is read only at that moment and is never stored or transmitted.
Vibration — used for haptic feedback when toggling the filter via the Quick Settings tile.
Schedule alarms — triggers the filter on and off at your configured times. The related boot permission re-registers your alarms after a restart so your schedule survives a reboot.
Location (approximate, optional) — used only to calculate local sunrise and sunset times when you enable the sun-based schedule. The calculation happens on your device. Your location is never stored, logged or transmitted.
The app stores your preferences locally: selected filter and intensity, schedule settings, sun-based schedule settings, your app exclusion list, and general display and theme options. This data never leaves your device, is not transmitted to any server, and is removed when you uninstall the app.
MONO offers a one-time in-app purchase handled entirely by Google Play. We receive no payment details. We only receive a confirmation that the purchase was made, which is stored locally on your device so that your purchased features stay unlocked. See the Google privacy policy.
We use no analytics tools, no crash reporting, no advertising and no trackers of any kind. We operate no server that receives your data.
Everything the app does happens locally on your device and involves no processing of personal data by us. Where the GDPR applies, we therefore act as controller only in the limited sense of providing the software; we have no processing operation on which to rely on a legal basis, because we receive no personal data. Google Play processes your purchase on its own legal basis, as described in Google's privacy policy.
Under the GDPR you have the right of access, rectification, erasure, restriction of processing, data portability and objection, as well as the right to lodge a complaint with a supervisory authority — in the Netherlands the Autoriteit Persoonsgegevens (autoriteitpersoonsgegevens.nl). Since we hold no personal data, there is usually nothing for us to access or delete. Requests concerning your purchase are best addressed to Google.
The app is not directed at children under the age of 16. We knowingly process no data of children.
We may update this policy occasionally. The current version is always available at this URL with a revised date at the top, and in the app under Settings → About and legal.
MONO is developed and operated by Yuri van der Putten (Goudboom Enterprise), an independent developer.
E-mail: info@goudboom.nl
Based in the Netherlands
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