Privacy Policy

LangReader Chrome Extension & Web App · Last updated: June 2026

LangReader is a language learning tool that helps you translate words, understand grammar, and build vocabulary while reading online. This policy explains what data we collect, how we use it, and your rights.

What data we collect

• Text you select: When you highlight a word or phrase and use the extension, that text is sent to our server to generate a translation and grammar explanation.
• Vocabulary and expressions: Words and expressions you choose to save are stored in our database linked to your account.
• Account information: If you register, we store your email address and a hashed password (we never store your password in plain text). If you sign in with Google, we store your Google account ID, display name, and profile picture URL.
• Usage data: We store which words you've practiced, your familiarity scores, and practice session history to power the spaced repetition system.
• Page context: When you select a single word, the extension captures the sentence it appears in to provide better example usage in practice. The full page content is never sent.

What we do NOT collect

• We do not track your browsing history.
• We do not collect data from pages where you have not selected text.
• We do not sell your data to third parties.
• We do not run ads.

How we use your data

• To provide translation and grammar explanations via the DeepSeek AI API. Selected text is sent to DeepSeek's servers to generate responses. See DeepSeek's privacy policy.
• To store your vocabulary and track your learning progress.
• To generate personalized practice questions based on your saved words.

Data storage

Your data is stored on our server hosted on Railway (US West region). Your extension settings (server URL, language preferences) are stored locally in your browser using chrome.storage.local and never leave your device.

Data retention and deletion

You can delete your account and all associated data at any time by contacting us. We will delete your data within 30 days of your request.

Third-party services

• DeepSeek AI — processes selected text to generate translations and explanations.
• Google OAuth — optional sign-in method. Only your email, name, and profile picture are shared with us.
• Railway — hosts our server infrastructure.

Contact

If you have questions about this privacy policy or want to request data deletion, contact us at: hancocksun@gmail.com

This policy applies to the LangReader Chrome Extension and the web application at langreader-production.up.railway.app.