LangHub Privacy Policy

LangHub is a browser extension and companion website that help you learn a language from the videos you watch. This policy explains what data LangHub handles, where it goes, and the choices you have. We keep it short because LangHub collects as little as possible.

What we store

Data	Where it lives	Why
Your saved words & phrases (the word, your translation, the example sentence, the source video title, the language)	In your browser. If you create an account, also in our database so they sync across your devices.	To build and review your vocabulary list.
Account email & an account ID	Our authentication provider (Supabase), only if you sign up or sign in with Google.	To identify your account and sync your words.
Settings and any optional API keys you enter (e.g. Anthropic or Gemini)	Only in your browser. Never sent to or stored on our servers.	To remember your preferences and let you use your own AI keys.

If you never create an account, your words and settings stay entirely on your device.

Services your data may pass through

To provide its features, LangHub sends the minimum necessary text to these providers — only when you use the related feature:

• Supabase — database & sign-in. Stores your account and saved words.
• Cloudflare — hosts the website and an AI request proxy.
• Google (Translate & Gemini) — receives subtitle lines or words you look up, to translate them and power optional AI features.
• Anthropic (Claude) — optional AI subtitle translation, used only if you supply your own API key.

Each provider receives only the text needed for the requested operation. We do not sell your data, show ads, or build advertising profiles.

Browser permissions

The extension requests only what it needs: access to YouTube and Netflix pages (and Netflix's subtitle servers) to show and read subtitles, the ability to observe subtitle-file requests, local storage for your words and settings, and sign-in via Chrome's identity API. It does not read your browsing history or activity on other sites.

Keeping and deleting your data

Saved words remain until you delete them. You can remove individual words in the app, clear your local data via your browser, or delete your account and its synced words by contacting us. We will delete account data on request.

Children

LangHub is not directed to children under 13 and we do not knowingly collect their data.

Changes

We may update this policy; we'll revise the date above when we do.

Contact

Questions or deletion requests: [email protected].