Privacy Policy

Effective date: June 10, 2026

1. Introduction

WordChain ("App", "we", "our", "us") is a mobile application designed to help users learn English vocabulary through a unique Tech Tree (dependency chain) system. This Privacy Policy explains how we collect, use, and protect your personal data when you use our application, available on both iOS (App Store) and Android (Google Play).

Effective date: June 10, 2026

Developer contact: merisoftb1@gmail.com

2. Information We Collect

2.1 Information Collected Automatically

• Device Information: Device model, operating system version, app version (collected via Firebase Analytics and device_info_plus)
• Usage Analytics: App open frequency, learning progress metrics, feature usage patterns, paywall interactions, feedback events (via Firebase Analytics)
• Advertising Identifiers: Device advertising ID for personalized ads (only with your consent under Apple's ATT framework on iOS 14.5+; via Google AD_ID permission on Android)
• Anonymous Authentication: We use Firebase Anonymous Authentication to enable AI-powered features. This generates a random anonymous identifier that is not linked to your personal identity.
• Crash & Performance Data: Technical logs for debugging and app stability improvement

2.2 Information You Provide

• Google Account Information: If you choose to use the Google Drive backup feature, we access your Google account name and email address solely for authentication. Your data is stored in your own Google Drive's appDataFolder (a private, hidden app-specific folder).
• Learning Data: Word lists, progress status, quiz results, spaced repetition schedules, activity statistics (stored locally on your device using Hive database)
• Feedback Data: If you submit negative feedback, we collect: your feedback text, premium status, learned word count, device information (brand, model, OS version), and timestamp. This is stored in Google Cloud Firestore.
• AI Interaction Data: When you use the Sentence Builder feature, your written sentences and questions are sent to Google's Gemini AI (via Firebase AI Logic SDK) for evaluation. These sentences are processed in real-time and cached locally on your device. We do not permanently store your sentences on our servers.

2.3 Information We Do NOT Collect

• Location data
• Contact lists or address book
• Photos, videos, or files
• Financial or payment information (payments are processed entirely by Apple/Google)
• Microphone recordings (the microphone permission listed in iOS is required by the Text-to-Speech audio framework; we do not record audio)

3. How We Use Your Information

• Providing core app functionality (vocabulary learning, spaced repetition system, Tech Tree progression)
• AI-powered sentence evaluation and mentor feedback (via Gemini)
• Improving user experience and fixing bugs
• Displaying advertisements to free-tier users
• Verifying subscription status
• Optional Google Drive backup service
• Sending local notifications for review reminders and streak maintenance
• Analyzing aggregate usage patterns to improve the app

4. Third-Party Services

Our app integrates the following third-party services, each with their own privacy policies:

5. Advertising & Tracking (ATT)

Our free tier displays advertisements through Google AdMob, including banner ads, interstitial ads, and rewarded video ads.

iOS (14.5+)

We request your permission through Apple's App Tracking Transparency (ATT) framework before accessing your device's advertising identifier for personalized ads. If you decline:

• The app continues to function fully
• Only non-personalized (contextual) ads are shown
• No restrictions are applied to any features

Android

We use the Google Advertising ID (AD_ID permission) for ad personalization. You can opt out of personalized ads through your device's Google settings.

Premium Subscribers

All advertisements are completely removed.

SKAdNetwork

On iOS, we use Apple's SKAdNetwork for privacy-preserving ad attribution measurement.

6. Data Storage & Security

• Local Storage: Your learning data is stored locally on your device using the Hive database (an encrypted-capable, lightweight NoSQL database)
• Cloud Storage: Feedback data is stored in Google Cloud Firestore with strict security rules (users can only access their own data)
• Google Drive Backup: If enabled, your data is encrypted in transit (HTTPS/TLS) and stored in your personal Google Drive's appDataFolder. Premium users receive automatic weekly backups.
• AI Processing: Sentence data sent to Gemini is processed in real-time and is subject to Google's AI data processing terms

7. Notifications

We send local notifications (not push notifications from a server) to:

• Remind you of words due for review (spaced repetition reminders)
• Encourage daily learning streaks
• Alert you about overdue reviews

Notification permissions are requested on both iOS and Android. You can disable notifications at any time through your device settings. On Android, we use SCHEDULE_EXACT_ALARM permission for precise review timing.

8. Children's Privacy

WordChain is not directed at children under 13 years of age. We do not knowingly collect personal information from children under 13. If you are a parent or guardian and believe your child has provided us with personal information, please contact us at the email below.

9. Your Rights

9.1 All Users

• Access: You can view all your learning data within the app
• Deletion: You can delete all local data by uninstalling the app. To request deletion of analytics data stored in Firebase, contact us via email.
• Opt-out of ads tracking: Decline ATT prompt (iOS) or adjust Google ad settings (Android)
• Disable notifications: Through device settings at any time
• Disconnect Google Drive: Sign out from within the app's backup settings

9.2 European Users (GDPR)

If you are located in the European Economic Area (EEA), you have additional rights under the General Data Protection Regulation (GDPR):

• Right to access your personal data
• Right to rectification of inaccurate data
• Right to erasure ("right to be forgotten")
• Right to restrict processing
• Right to data portability
• Right to object to processing

Our legal basis for processing: legitimate interest (app functionality), consent (advertising tracking), and contract performance (subscription services).

9.3 California Users (CCPA)

If you are a California resident, the California Consumer Privacy Act (CCPA) grants you:

• Right to know what personal information is collected
• Right to request deletion of personal information
• Right to opt-out of the sale of personal information
• Right to non-discrimination for exercising your rights

10. Data Retention

• Local data: Retained until you uninstall the app or manually clear app data
• Firebase Analytics: Retained for up to 14 months (Google's default retention period)
• Firestore feedback data: Retained indefinitely for product improvement; deletion available upon request
• Google Drive backups: Retained in your personal Drive until you delete them or disconnect the service
• AI interaction data: Processed in real-time; cached locally for up to 200 entries, then oldest entries are automatically purged

11. Changes to This Policy

We may update this Privacy Policy from time to time. When significant changes are made, we will notify you through an in-app notification. The current policy is always available on this page.

12. Contact Us

For privacy-related questions, data access requests, or data deletion requests: