Privacy Policy

Last updated: March 27, 2026

1. Introduction

Welcome to Nihongo Study Guide ("we," "our," or "us"). We are committed to protecting your privacy and ensuring a safe experience while using our mobile application and website (collectively, the "Service"). This Privacy Policy explains how we collect, use, and safeguard your information when you use our Service.

2. Information We Collect

We collect the following types of information to provide and improve our Service:

Account Information: When you create an account, we collect your email address and display name. You may also sign in using Google OAuth, in which case we receive your basic profile information (name and email) from Google.
Learning Data: We store your study progress, quiz scores, kanji and vocabulary learning history, grammar progress, and JLPT level preferences to personalize your learning experience.
Feedback Data: When you submit feedback or contact support, we collect the message content, subject, and optionally your email address for follow-up.
Device Information: We may collect basic device information such as device type, operating system version, and app version for troubleshooting and compatibility purposes.
Usage Data: We collect anonymized usage patterns such as study streaks, session duration, and feature usage to improve our Service.

3. How We Use Your Information

We use the information we collect for the following purposes:

To provide, maintain, and improve the Service
To sync your learning progress across devices
To personalize your study experience based on your JLPT level and progress
To respond to your feedback and support requests
To send study reminders and notifications (only with your permission)
To analyze usage patterns and improve our content and features

4. Data Storage and Security

Your data is securely stored using Supabase, a trusted cloud database platform with enterprise-grade security. We implement appropriate technical and organizational measures to protect your personal information against unauthorized access, alteration, disclosure, or destruction. All data transmission between the app and our servers is encrypted using HTTPS/TLS protocols.

5. Third-Party Services

We use the following third-party services to operate and improve our Service:

Supabase: For user authentication, database storage, and cloud functions. Supabase Privacy Policy
Google OAuth: For optional sign-in functionality. Google Privacy Policy
Resend: For sending email notifications related to feedback and support. Resend Privacy Policy
Expo: For app delivery and updates. Expo Privacy Policy

We do not sell, trade, or rent your personal information to third parties. We do not use your data for advertising purposes.

6. Data Retention

We retain your personal information for as long as your account is active or as needed to provide you the Service. If you wish to delete your account and all associated data, you can do so from the Account Settings within the app, or by contacting us at support@nihongostudyguide.com. Upon account deletion, your data will be permanently removed from our servers within 30 days.

7. Children's Privacy

Our Service is designed for users of all ages who are interested in learning Japanese. We do not knowingly collect personal information from children under 13 without parental consent. If we discover that a child under 13 has provided us with personal information without parental consent, we will promptly delete that information. If you believe your child has provided us with personal information, please contact us at support@nihongostudyguide.com.

8. Your Rights

You have the following rights regarding your personal information:

Access: You can view your personal data within the app at any time.
Correction: You can update your display name and profile information in Account Settings.
Deletion: You can request deletion of your account and all associated data.
Data Export: You can request a copy of your data by contacting our support team.
Opt-out: You can disable notifications and study reminders at any time from your device settings.

9. Notifications and Permissions

The app may request the following permissions:

Internet Access: Required for syncing data, authentication, and loading content.
Notifications: Optional, used for study reminders. You can enable or disable these at any time.
Vibration: Used for haptic feedback during quizzes and interactions.

10. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of any significant changes by posting the new Privacy Policy on this page and updating the "Last updated" date. Your continued use of the Service after any changes constitutes acceptance of the updated policy.

11. Contact Us

If you have any questions or concerns about this Privacy Policy, please contact us: