Privacy Policy

Effective date: 2026-09-08

BunSense ("the Extension") helps you read and watch Japanese: furigana, translation, grammar help, a vocabulary notebook, an AI assistant, video transcripts on YouTube, and text-to-speech. This policy explains what data the Extension handles and where it goes.

Data We Handle

• Text you act on: text you select or hover on a page, and transcript lines you open on YouTube (plus nearby text for context).
• Notebook entries: words and grammar you save, stored in your browser. Chrome may carry a recent portion to your other devices if you use Chrome sync. You can export the notebook at any time.
• Extension settings: your preferences and any notes you write for the AI assistant, stored in your browser. Chrome may sync them to your other devices if you use Chrome sync.
• API keys (optional): keys you enter for AI or voice providers are stored only on your device, never synced, and sent only to that provider.

How We Use Data

Only to provide the Extension's features: furigana, translations, glosses and grammar explanations; the notebook; the AI assistant; video transcripts; and text-to-speech. We do not use your data for advertising, profiling or training.

External Services

Depending on the feature you use, text is sent to these third parties. Each receives only the text needed for that request and handles it under its own privacy policy.

• Translation (default engine, no key needed): Chrome's built-in translator, Microsoft Bing Translator, and Google Translate.
• AI features (only with your key): OpenAI, DeepSeek, or Anthropic (Claude), whichever you chose in Settings. Used for the AI assistant, AI grammar and vocabulary notes on video lines, and translation when the engine is set to AI.
• Text-to-speech (only with your key): OpenAI, Google Gemini, or Microsoft Azure Speech.
• Dictionary lookups: Jisho.org.

Feedback

If you use the feedback form, it opens a prefilled e-mail in your own mail service. The page URL, browser name and Extension version are added to the message so we can reproduce problems; you can edit or remove them before sending.

Data Sharing

We do not sell or share your data with advertisers or anyone else. Data leaves your device only for the requests described above, and only when you use those features.

Data Retention and Deletion

• Settings and notebook entries stay in your Chrome storage until you delete them in the Extension or uninstall it.
• API keys are stored locally and can be removed in Settings at any time.

Security

All connections use HTTPS. API keys never leave your device except to the provider they belong to. Still, no method of transmission over the Internet is 100% secure.

Children's Privacy

The Extension is not intended for children under 13 and does not knowingly collect personal information from children.

Changes to This Policy

We may update this policy when the Extension changes. The effective date above is updated with each change; the release notes say what changed.

Contact

If you have questions, contact: kuroskreuz@gmail.com