Privacy Policy

Last updated: October 19, 2026

The short version

UnderKey collects no personal data. Your documents, patterns, and metadata are encrypted on your device and never sent to us. We don't run servers that could receive them. The app uses Google ML Kit for on-device text recognition; on Android, Google Play Services may perform a one-time download of a text recognition component.

What the app collects

Nothing. The UnderKey app stores everything — your documents, photos, notes, patterns, and expiry dates — locally on your device, encrypted with AES-256-GCM. The app has no servers, no accounts, and no analytics.

Website analytics

This website (underkey.app) uses analytics services to understand how visitors use our site. These analytics are separate from the UnderKey app and do not affect your app data or privacy.

Umami Analytics (self-hosted)

We use Umami, a privacy-focused, self-hosted analytics service. Umami does not use cookies and does not collect personally identifiable information. It tracks page views, referrers, device types, and geographic regions (country-level) without identifying individual visitors.

Google Analytics

With your consent, we use Google Analytics to understand site usage patterns. Google Analytics sets cookies to track visits and may collect information such as your IP address (anonymized), browser type, device information, pages visited, and time spent on pages. Google Analytics data is subject to Google's Privacy Policy.

Cookie consent: Google Analytics runs only after you accept cookies via the consent banner. You can decline or revoke consent at any time using the "Cookie Settings" link in the footer.

Ahrefs

We use Ahrefs Web Analytics and/or Ahrefs Webmaster Tools to monitor site performance and search visibility. Ahrefs Web Analytics is cookieless and does not collect personally identifiable information. See Ahrefs Privacy Policy.

Important: Website analytics do not have access to your UnderKey app data. Your documents, patterns, and photos remain encrypted on your device and are never sent to any analytics service or to us.

What third parties collect

When you purchase UnderKey Pro, payment processing is handled by:

• Apple App Store (iOS): subject to Apple's Privacy Policy.
• Google Play Store (Android): subject to Google's Privacy Policy.
• RevenueCat: we use RevenueCat to manage subscriptions and verify purchases. RevenueCat processes your purchase receipt and an anonymous user identifier, but does not have access to your documents or personal information. See RevenueCat's Privacy Policy.

We never see your payment details, email address, or any personally identifying information from these services.

How your data is stored

All documents, photos, secure notes, and metadata are encrypted using AES-256-GCM and stored only on your device. Your unlock pattern is never stored anywhere — it derives the encryption key each time you unlock a vault.

UnderKey does not sync to iCloud, Google Drive, or any cloud service. If you delete the app or lose your device, your data cannot be recovered by us or anyone else.

Permissions

UnderKey requests the following device permissions:

• Camera: to scan and photograph documents for encryption and storage. The document scanner uses on-device edge detection to frame documents automatically.
• Photo Library: to import existing photos or documents from your device.
• Files/Documents: to import documents from your device's file system.
• Notifications: to remind you before documents expire (optional; reminders are created locally and never sent to a server).

All permissions are optional. You can deny them and still use the app, though some features will be unavailable.

On-device text recognition (OCR)

UnderKey uses Google ML Kit Text Recognition to suggest expiry dates when you scan or photograph a document. This processing happens entirely on your device:

• UnderKey does not upload your documents or recognized text. Your documents and the text recognized from them are processed on your device and are not sent to UnderKey. We never see your documents or the recognized text. For Google ML Kit's own data practices, see Google's ML Kit Terms.
• One-time download on Android: On Android devices, Google ML Kit may download a text recognition component or model via Google Play Services the first time you use the feature. This is a one-time system-level download managed by Google Play Services, not UnderKey. Once downloaded, all text recognition runs on-device.
• iOS scanning and text recognition: On iOS, the document scanner uses Apple's built-in VisionKit, and text recognition uses Google ML Kit bundled inside the app, running on-device. No additional downloads are required.

The OCR feature is optional — you can always enter expiry dates manually or skip them entirely.

Screenshot and screen recording protection

• Android: UnderKey blocks screenshots and screen recordings while the app is unlocked, and blurs the app preview in the app switcher.
• iOS: iOS does not provide a way for third-party apps to fully block screenshots. UnderKey blurs the app preview in the app switcher, but cannot prevent screenshots while the app is in use.

Children's privacy

UnderKey does not knowingly collect any information from anyone. We don't have servers or accounts, so there is nothing to collect.

Changes to this policy

We may update this privacy policy from time to time. We'll post the updated policy in the app and on this page with a new "Last updated" date.

Contact

If you have questions about this privacy policy, contact us at [email protected].