Privacy Policy

Last updated: August 21, 2025

Information We Collect

We collect the following information from users to provide and improve our language learning services:

  • Account information (email address, username, profile information)
  • External service IDs and information that users authorize to be shared through external service privacy settings
  • Device and OS information including device identifiers, OS-generated IDs, device type, and device identifiers
  • Learning progress and vocabulary data
  • Voice recordings for pronunciation practice (processed locally when possible)
  • App usage history including session duration, input history, and learning activities
  • Website behavior including session time, navigation patterns, and interaction data
  • Cookie-generated identification information for website functionality
  • Purchase history for premium features and subscriptions

How We Use Your Information

We use the collected information for the following purposes:

  • Service registration, user authentication, and identity verification
  • Managing your service usage history and learning progress
  • Processing payments for premium features
  • Analyzing user behavior to maintain and improve our services
  • Providing personalized learning experiences and recommendations
  • Tracking your progress across devices with cloud synchronization
  • Improving our AI conversation partners and language learning algorithms
  • Sending service announcements and important updates
  • Responding to customer inquiries and providing support
  • Addressing violations of our terms of service or applicable laws
  • Notifying users of service changes, suspension, termination, or contract cancellation
  • Communicating changes to our terms and conditions
  • General service provision, maintenance, protection, and improvement

Security Measures

We implement industry-standard security measures to protect your personal information. For specific details about our security measures, please contact us using the information provided below, and we will respond individually in accordance with applicable laws. Your learning progress is encrypted and securely stored in the cloud with automatic backups.

Third-Party Data Sharing

We do not provide personal data (as defined in Article 16, Paragraph 3 of the Personal Information Protection Act) to third parties (including parties located outside Japan) without prior user consent, except in the following cases:

  • When we outsource personal data processing to external parties
  • When our company or services are acquired
  • When jointly using data with business partners (specific joint usage will be separately disclosed)
  • When legally permitted by law

Third-Party Services

Butango integrates with trusted third-party services for enhanced functionality:

  • Firebase for secure data storage and authentication
  • OpenAI, Google, and ElevenLabs for AI-powered language features
  • Google Analytics for usage analysis and service improvement
  • Payment processors for subscription and purchase processing
  • Cloud storage services for cross-device data synchronization

Analytics Tools

We use Google Analytics to analyze user access patterns. Google Analytics uses cookies to collect traffic data anonymously and does not identify individuals. You can refuse this data collection by disabling cookies in your browser settings. For more information about Google Analytics, please visit:
https://marketingplatform.google.com/about/analytics/terms/jp/

Your Rights

You have the right to access, correct, suspend usage, or delete your personal information. For such requests, please contact us at the email address provided below. We will verify your identity through methods we specify, such as presenting a driver's license. Please note that information disclosure requests are subject to an administrative fee of 1,000 yen per request, regardless of whether information is disclosed.

Privacy Policy Changes

We may change this privacy policy as necessary. When changes are made, we will notify users of the effective date and content of the updated privacy policy through appropriate means.

Contact Information

If you have questions about this Privacy Policy or wish to exercise your rights regarding your personal information, please contact us at:

Email: kei.fujikawa@kboy.jp

Business Entity: KBOY Inc.
Representative: Kei Fujikawa
Address: 4-41 Midpoint Hatagaya, Keio Hatagaya Building, 1-2-2 Hatagaya, Shibuya-ku, Tokyo 151-0072, Japan