Privacy Policy

Last updated: November 7, 2025

Introduction

This application "Russian Cases & Declension" (hereinafter "the App") respects user privacy. This Privacy Policy explains what information the App collects and how it is used.

Information We Collect

1. Automatically Collected Information

Anonymous User ID: The App uses Firebase anonymous authentication to assign each user a unique anonymous ID. This ID cannot identify individuals.

2. Information Stored in the Cloud

The App stores only the following information in the cloud (Google Cloud Firestore):

• Purchase Information: In-app purchase history (A1 level purchase status, downloaded levels)

3. Information Stored Only on Your Device

The following information is stored only in local storage on your device and is not sent to the cloud:

• Learning Data: Bookmarked words, learning progress, quiz results
• Notes: Personal notes that users add to each word
• App Settings: Language settings, dark mode settings, etc.

4. Content Delivery

The App may use Firebase Storage to deliver additional vocabulary data (A2/B1/B2 levels) for download. This data consists of educational content and does not include personal information.

5. Data Export and Import

The App provides functionality for users to export and import their notes data:

• Export: Save notes data as a file on your device
• Import: Restore notes data from a previously saved file
• Share: Share exported files with other apps or devices

These operations are performed entirely at the user's discretion, and data is not automatically sent externally.

6. Usage Analytics and Crash Reporting

The App uses the following tools for service improvement:

Google Firebase Analytics

Collects anonymous usage statistics:

• App launch count
• Screen transitions and feature usage
• Basic usage patterns

Firebase Crashlytics

Automatically detects and reports app crashes and errors:

• Crash occurrence
• Error logs
• Device information (model, OS version)

This information is anonymized and cannot identify individuals. Collected data is used only for improving app stability and functionality.

For more details, please see:

• Firebase Analytics Data Collection
• Firebase Crashlytics Privacy

7. Information We Do NOT Collect

The App does not collect the following information:

• Name, email address, phone number
• Location information
• Device identifiers (except anonymous user ID and anonymous device information collected by analytics tools)
• Access to contacts, camera, or other device features

Third-Party Services Used

Audio Content

The App includes pre-generated audio files for Russian pronunciation:

Audio Sources:

• Google Text-to-Speech
• ElevenLabs

All audio files are pre-generated and embedded within the app. No user data or device information is transmitted to these services during app usage. The audio playback is performed entirely offline using the pre-recorded files.

Purpose of Use

Collected information is used only for the following purposes:

• Saving and displaying learning progress
• Managing in-app purchases
• Providing and improving app functionality
• App usage analysis (Firebase Analytics)
• Crash and error detection and fixing (Firebase Crashlytics)
• Data export and import when chosen by the user

Information Storage and Protection

Cloud Storage

• Purchase information is encrypted and stored in Google Cloud Firestore
• Data is protected with appropriate security measures
• Each user can only access their own data

Local Storage

• Learning data, notes, and app settings are stored only on the device
• This data is not sent to the cloud
• Data is deleted when the app is uninstalled

Third-Party Disclosure

The App does not share user information with third parties except in the following cases:

• Firebase/Google Cloud: Purchase information storage, usage analytics, crash reporting
• Firebase Privacy Policy
• Google Cloud Privacy Policy
• Apple/Google: In-app purchase processing
• Apple Media Services Terms
• Google Play Terms of Service
• When required by law

When users share data using the export function, the responsibility lies with the user.

These third-party services operate under their own privacy policies.

User Rights

Data Deletion

Deleting Learning Data

You can delete your learning history, bookmarks, and settings using the "Delete Learning Data" option in the Settings screen. This data will also be deleted when the app is uninstalled.

About Purchase Information

Purchase information stored in the cloud and anonymous user accounts cannot be deleted from within the app. This data is linked to an anonymous ID that cannot identify individuals and is retained for the in-app purchase restoration feature.

Data Export

You can export your notes data at any time using the app's built-in functionality.

Children's Privacy

This app is suitable for all ages 4 and above, but does not collect any personally identifiable information (name, email address, etc.). The app uses only anonymous authentication, with purchase information stored in the cloud and learning data stored securely on the device.

Changes to Privacy Policy

This Privacy Policy may be changed without notice. When changes are made, the "Last updated" date on this page will be updated. We recommend checking this page regularly.

Governing Law

This policy is created based on Japan's Act on the Protection of Personal Information and related laws.

Contact Us

If you have any questions or concerns about privacy, please contact us at:

Email: [grammarforge.apps@gmail.com]

Last updated: February 4, 2025