Privacy Policy

Last updated: July 14, 2026

TierReader ("we", "our", or "us") is committed to protecting your privacy. This policy explains what information we collect, how we use it, and your rights as a user of the TierReader iOS app.

Information We Collect

We collect only the minimum information necessary to provide the service:

• Diagnostic data — in release builds, TierReader sends anonymized diagnostic logs (error messages, device model, iOS version, app version, and a randomly generated installation identifier) to our backend, which forwards them to Axiom, our log analytics provider. This data is not linked to your identity and is used only to diagnose crashes and errors.
• Reading activity — passages you generate, words you mark as known or unknown, and quiz results. This data is stored locally on your device and, if you enable a sync option, in your chosen cloud storage (iCloud, Google Drive, or Dropbox).
• Purchase information — subscription status for the paid tier is managed by RevenueCat. We do not store your payment details.
• Advertising identifier (IDFA) — if you consent to tracking via the App Tracking Transparency prompt, Google AdMob may use your device's advertising identifier to serve personalized ads on the free tier. If you decline, non-personalized ads are shown instead.

Information We Do Not Collect

• We do not collect precise location data.
• We do not collect contacts, photos, or any data unrelated to language learning.
• We do not sell your personal data to third parties.

How We Use Your Information

• To generate personalized reading passages via the AI backend.
• To sync your vocabulary and progress across your iOS devices.
• To manage your subscription through RevenueCat.
• To show ads on the free tier via Google AdMob (personalized only with your consent).
• To improve app performance and fix bugs.

Advertising

The free tier of TierReader displays rewarded ads served by Google AdMob. When you first launch the app, you will be asked for permission to track your activity across apps and websites (App Tracking Transparency). If you grant permission, AdMob may use your advertising identifier (IDFA) to show personalized ads. If you decline, ads are still shown but are not personalized. You can change this permission at any time in your iOS Settings under Privacy & Security → Tracking.

On-Device Processing

TierReader performs translation entirely on your device. On iOS 18 and later it uses Apple's on-device Translation framework. On earlier versions of iOS, and on Android, it uses Google ML Kit's on-device translation models; these models are downloaded once from Google and then run offline. In every case the translation itself happens on your device — the text you are reading is never sent to an external server for this feature. Text-to-speech also runs entirely on-device using the operating system's speech synthesizer.

Third-Party Services

TierReader uses the following third-party services, each governed by their own privacy policies:

• Google Gemini — used to generate reading passages. Prompts are sent to our own backend server, which forwards them to Google's Gemini API. Prompts contain only your selected level, genre, and target vocabulary — no personal information. See Google's Privacy Policy.
• Google AdMob — used to serve rewarded ads on the free tier. AdMob may use your advertising identifier (IDFA) to show personalized ads if you have granted tracking permission. See Google's Privacy Policy.
• Firebase Analytics — used to collect anonymized usage analytics (e.g. screens visited, features used). No personally identifiable information is linked to analytics events. See Firebase Privacy Policy.
• Axiom — used to collect anonymized diagnostic and error logs to diagnose crashes and improve reliability. Logs contain no personally identifiable information. See Axiom's Privacy Policy.
• RevenueCat — used to manage paid subscriptions and purchase verification. See RevenueCat's Privacy Policy.
• Apple iCloud — optional sync for your vocabulary and reading history. Your iCloud data is governed by Apple's Privacy Policy.
• Google Drive — optional sync and export. TierReader creates a "Tier Reader" folder in your Drive using the drive.file scope and stores only files it creates. Governed by Google's Privacy Policy.
• Dropbox — optional sync for your vocabulary and reading history. Data stored in your own Dropbox account is governed by Dropbox's Privacy Policy.

Google API Data

TierReader's use of Google Drive is limited to backing up and restoring your vocabulary and reading progress. Specifically:

• Scope requested — TierReader requests the drive.file scope, which allows the app to create and manage only the files it creates. We cannot access any other files in your Google Drive.
• What we store — TierReader creates a folder named "Tier Reader" in your Google Drive and stores only your vocabulary exports (CSV/TSV) and a sync file (JSON) containing your reading progress. No other data is uploaded.
• Why we need it — to allow you to back up and restore your progress across devices or after reinstalling the app, and to export your vocabulary data.
• Sharing — data accessed via Google APIs is never shared with third parties, used for advertising, or used for any purpose other than providing the sync and export features within TierReader.
• Revoking access — you can revoke TierReader's access to your Google Drive at any time via your Google Account permissions page. Revoking access does not delete files already in your Drive.

TierReader's use of Google user data complies with the Google API Services User Data Policy, including the Limited Use requirements.

Data Storage & Security

Your reading data is stored locally on your device. If you enable cloud sync, data is stored in your chosen provider (iCloud, Google Drive, or Dropbox) under your own account — we do not have access to it. We use industry-standard practices to secure any data transmitted to our backend.

Data Retention & Deletion

You can delete all your data at any time by uninstalling the app. TierReader stores your data locally on your device, so deleting the app removes it. If you have cloud sync enabled, you can remove synced data directly from iCloud Settings, Google Drive, or Dropbox. Cancelling a paid subscription does not delete your data.

Children's Privacy

TierReader is not directed at children under 13. We do not knowingly collect personal information from children under 13.

Changes to This Policy

We may update this privacy policy from time to time. We will notify you of significant changes via an in-app notice. Continued use of the app after changes constitutes acceptance of the updated policy.

Contact Us

If you have any questions about this privacy policy, please contact us at support@tierreader.com.