# Privacy Policy for LEX: Learn English Grammar **Effective Date:** August 12, 2026 **Last Updated:** August 12, 2026 Welcome to **LEX: Learn English Grammar** ("we," "our," or "us"). We are committed to protecting your privacy and providing a safe, transparent mobile application experience. This Privacy Policy explains how **LEX: Learn English Grammar** collects, uses, discloses, and protects your information when you use our mobile application ("App") available on the Google Play Store and Apple App Store. --- ## 1. Summary of Key Principles - **No Personal Identifiers Required:** We do not require you to register with your real name, email address, phone number, or social media accounts. - **Offline-First:** Your core learning progress, quiz scores, and saved vocabulary are stored locally on your device. - **Anonymous Authentication:** We generate an anonymous, random device identifier (UUID) to sync your subscription status and enable public comment features. - **Voice Privacy:** Speech recognition and audio evaluation (microphone access) are processed on-device or via your system speech engine and are **never** recorded or stored on our servers. --- ## 2. Information We Collect ### A. Data Collected Automatically (Anonymous Account) - **Anonymous User ID (UUID):** Upon launching the App, a random unique identifier is created via Supabase. This UUID contains no personally identifiable information (PII) and allows us to: - Restore your premium subscription across reinstalls on the same device. - Attribute public comments you choose to post on lesson discussion boards. ### B. Data Stored Locally on Your Device - **App Progress & Metrics:** Your lesson completion status, quiz attempt scores, starred vocabulary words, unlocked lessons, interface language preference, and theme selection are saved locally on your device via `AsyncStorage`. ### C. User-Generated Content (UGC) - **Public Comments:** If you voluntarily submit a comment or question on a lesson discussion board, the text of your comment, the target language context, and your anonymous user UUID are transmitted to and stored on our secure backend database (Supabase). Comments are public and visible to other users of the App. ### D. Audio & Microphone Access - **Speech Recognition:** If you participate in spoken exercises, the App requests microphone permission (`expo-speech-recognition` / `expo-speech`). Audio input is processed in real time by your device's native speech recognition engine to evaluate your spoken English pronunciation. Audio recordings are **not** collected, saved, or transmitted to our servers. ### E. Advertising & Device Identifiers - **Google AdMob:** For non-subscribed (free tier) users, we display rewarded video advertisements to allow temporary lesson unlocks. Google AdMob may collect and process device identifiers (such as the Google Advertising ID / GAID), IP address, and app usage data to serve personalized or non-personalized ads, perform fraud detection, and measure ad performance. ### F. Purchase & Subscription Data - **RevenueCat & Google Play In-App Billing:** When you purchase a subscription or lifetime access, transaction details (purchase token, entitlement status, product ID, transaction timestamp) are processed securely through Google Play In-App Billing and RevenueCat. We **do not** receive or store your credit card or financial account numbers. --- ## 3. How We Use Your Information We use the collected information solely for the following purposes: - **Core Functionality:** To display lessons, record exercise progress, evaluate spoken answers, and provide localized interface content. - **Monetization & Entitlements:** To verify your subscription status and deliver rewarded video ads for lesson unlocks. - **Community Discussion:** To display public comments and facilitate Q&A between learners. - **App Maintenance:** To debug issues, enforce community safety guidelines, and improve app stability. --- ## 4. Third-Party Services & Data Sharing We do not sell, rent, or trade your personal data. We integrate with trusted third-party SDKs that process data in accordance with their respective privacy policies: | Third-Party Provider | Purpose | Data Processed | Privacy Policy Link | | :--- | :--- | :--- | :--- | | **Supabase** | Backend Database & Anonymous Auth | Anonymous User UUID, Public Comments | [Supabase Privacy Policy](https://supabase.com/privacy) | | **RevenueCat** | Subscription & In-App Purchase Management | Anonymous User UUID, Purchase Tokens, Entitlement Status | [RevenueCat Privacy Policy](https://www.revenuecat.com/privacy) | | **Google AdMob** | Rewarded Video Advertising | Advertising ID (GAID), IP Address, Ad Performance Data | [Google Privacy Policy](https://policies.google.com/privacy) | | **Expo Framework** | Mobile Infrastructure & Native Module Integration | Device Diagnostics & System Features | [Expo Privacy Policy](https://expo.dev/privacy) | --- ## 5. User-Generated Content (UGC) & Moderation To maintain a safe and respectful community environment on lesson discussion boards, LEX provides built-in safety tools: - **Content Reporting/Flagging:** Users can flag inappropriate, abusive, spammy, or off-topic comments. Flagged content is queued for administrative review and removal. - **User Blocking:** Users can block any commenter. Blocking immediately hides all present and future comments from that user across your sessions. --- ## 6. Children's Privacy (COPPA & Google Play Families Policy) **LEX: Learn English Grammar** is a general-audience educational application. We do not knowingly collect personal information from children under the age of 13 (or under 16 in the EU/EEA). If you are a parent or legal guardian and believe your child has submitted personal data to us, please contact us immediately so we can promptly delete such information. --- ## 7. Data Security We implement industry-standard security measures to protect data in transit and at rest: - **Encrypted Transmission:** All network communication between the App and third-party backends (Supabase, RevenueCat, Google AdMob) uses HTTPS with TLS encryption. - **Encrypted Local Assets:** Educational lesson data bundled within the App is secured using AES-256-CBC encryption. --- ## 8. Data Retention & Data Deletion Request (Google Play Compliance) We retain anonymous UUID profiles and public comments only for as long as necessary to provide app services. ### How to Request Data Deletion: Because we do not collect email addresses or passwords, your account data consists of your anonymous User UUID, local progress data, and any public comments posted under that UUID. 1. **Clear Local Data:** You can clear all local progress and settings at any time by uninstalling the App or clearing the App storage/cache in your Android device settings (**Settings > Apps > LEX > Storage > Clear Data**). 2. **Request Deletion of Cloud Data / Public Comments:** To request complete removal of your anonymous user record or public comments from our Supabase database, please send an email to: - **Contact Email:** `atommes.dev@gmail.com` - **Subject Line:** Data Deletion Request - LEX App - **Body:** Provide your request details (and your anonymous User ID displayed at the bottom of the Profile screen, if available). We will process and confirm deletion within 30 days. --- ## 9. Changes to This Privacy Policy We may update our Privacy Policy periodically to reflect changes in legal requirements, third-party policies, or app features. Any updates will be posted on this page with a revised "Last Updated" date. We encourage you to review this policy periodically. --- ## 10. Contact Us If you have questions, concerns, or requests regarding this Privacy Policy or our data practices, please contact us at: - **Developer Name:** Atom / atommes - **Email:** `atommes.dev@gmail.com` - **Application:** LEX: Learn English Grammar