Privacy Policy

Effective Date: June 03, 2026

Nihongo Buddy is committed to protecting your privacy. This privacy policy explains what data we collect, how we use it, and how it is protected.

Information We Collect

• LINE Messages: Messages sent to the Nihongo Buddy LINE bot are processed based on the mode:
  - Translation Mode (default): Messages are processed for translation and not stored.
  - Conversation Mode (@Nihongo Buddy): By default, messages are processed for a reply and are not stored for future memory. If a group enables Memory in the menu and accepts the warning, Nihongo Buddy stores an encrypted rolling history of up to 10 recent messages per group in Firestore. The stored memory cannot be read directly in Firestore by humans, including Nihongo Buddy admins. It is decrypted by the app only when building the OpenAI request.
• Group Identifiers: We store the group ID from LINE to track usage per group and manage chat credit balances. We do not collect individual user IDs, names, or personal identifiers.
• Chat Activity: We count how many messages are sent to determine when credits are used. This total is stored in memory temporarily and synced to our database.
• Payment Data: Stripe handles all payment transactions. We do not store or have access to your card number, billing address, or any sensitive payment information.

How We Use Your Data

• To track credit usage and limit access if the credit balance runs out.
• To provide appropriate translations using OpenAI's language model.
• To maintain conversation memory only when a group has enabled Memory and accepted the warning.
• To process payment-related updates and reflect changes in credit balances.

Third Parties

We use the following third-party services:

• OpenAI: For generating translations and conversation responses based on user input.
• Stripe: For secure payment processing.
• Google Cloud (Firebase): For secure storage of group credit data, settings, and encrypted opt-in memory.

Data Retention

Translation Mode: Messages are not stored after translation. Conversation Mode: Memory is off by default. If Memory is enabled in the menu, Nihongo Buddy stores an encrypted rolling history of up to 10 recent messages per group in Firestore to provide memory-aware responses. The stored memory cannot be read directly in Firestore by humans, including Nihongo Buddy admins. It is decrypted by the app only when building the OpenAI request. Turning Memory off clears the stored memory for that group. Group-level data such as total chats, credit balances, settings, and encrypted opt-in memory are stored in Firestore. We retain only what is necessary to maintain the service.

Contact

If you have any questions or concerns about this privacy policy, please discontinue the use of Nihongo Buddy now!