Privacy Policy
Last Updated: February 24, 2026
Your vocabulary, notes, files, and settings never leave your device. We don't collect, store, or even see your data.
1.Introduction
LangGrove ("we," "us," or "our") is committed to extreme privacy. This Privacy Policy explains how we handle information when you use the LangGrove browser extension and the reader tool at reader.langgrove.com (collectively, the "Service"). By using the Service, you consent to the practices described here. If you do not agree, please uninstall the Extension or stop using the reader immediately.
2.Information We Collect
A. Vocabulary Data, Notes, Reader Files, and Local Settings (Stored Locally Only)
All your saved words, pronunciations, translations, notes or annotations, toggles (highlight/translate/pronunciation), color customizations (highlight, translation, pronunciation), and any other local preferences are stored exclusively in your browser's local storage on your device.
When using the reader at reader.langgrove.com, any files you upload (PDF, EPUB, DOCX, HTML, Markdown, or TXT) are processed entirely in your browser. Files are never uploaded to our servers or any cloud storage — processing, parsing, and highlighting happen locally using your device's resources.
Highlighting, note-taking, toggles, and color customizations occur solely using your locally saved vocabulary and settings. No file content, document text, notes, vocabulary data, word counts, local settings, or any related usage metrics are ever transmitted to us.
We never collect, access, transmit, store, or see your vocabulary, notes, uploaded file contents, toggles, colors, or any learning-related data.
B. Account and Subscription Information
When you subscribe to a paid plan or access features requiring an account:
- We use Google OAuth ("Sign in with Google") for authentication. Google provides us with your email address and basic profile information (e.g., user ID) necessary for account creation and subscription linking. We do not receive or store your Google password or any other sensitive Google data.
- Email address and basic account details for authentication and subscription management.
- Subscription plan status (tier and expiry) received from Polar.sh after payment.
When the Extension or reader fetches your plan information, it sends only your authenticated account identifier (derived from Google OAuth). No local vocabulary data, notes, word counts, file contents, toggles, colors, or usage metrics are ever transmitted.
C. Technical Information
We may automatically collect limited, anonymized technical data such as: Browser type and version, Extension version, Aggregated crash reports (to improve stability). This data cannot identify you personally and is not linked to your local vocabulary, notes, files, or settings.
3.How We Use Your Information
- To authenticate your account via Google OAuth and deliver paid features (e.g., higher highlighting limits).
- To process and manage subscriptions via Polar.sh.
- To send critical service notices (e.g., plan changes or updates).
- To enable local highlighting, note-taking, toggles, and color customizations in the Service, without any server involvement.
- To improve the Service using aggregated, anonymized data only.
We do not use your data for advertising, profiling, or any other non-essential purpose.
4.How We Share Your Information
- We do not sell any personal information.
- Payment and subscription data is shared only with Polar.sh (our Merchant of Record) to complete transactions.
- Authentication is handled via Google OAuth; limited data (email, user ID) is received from Google in accordance with their OAuth scopes. Your Google account is governed by Google's Privacy Policy.
- We may disclose information if required by law or to protect our rights.
- In a business transfer (merger, acquisition, etc.), data would be protected under the same privacy standards.
5.Data Storage and Security
- All vocabulary, notes, uploaded files, toggles, and color settings in the Service remain in browser memory or local storage only during your session/use and are not persisted on our servers.
- Account and subscription data is stored on secure servers with industry-standard encryption.
- We use reasonable security measures, but no system is 100% secure. You are responsible for securing your device and browser.
6.Your Rights and Choices
- Local data: View, edit, delete your saved words, notes, toggles, colors, or clear uploaded file data anytime in the Extension or reader settings. Uninstalling the Extension or clearing browser data removes everything locally.
- Account data: Access, correct, or delete your account via settings or by contacting us.
- Uninstall / Stop Use: Immediately stops any data interaction.
- Subscription management: Cancel or manage via your Polar customer portal.
7.Children's Privacy
The Service is not directed to children under 13. We do not knowingly collect data from children under 13. If we become aware of such data, we will delete it.
8.Changes to This Privacy Policy
We may update this Policy. Material changes will be notified via the Extension, reader.langgrove.com, langgrove.com, or email. Continued use constitutes acceptance.
9.Contact Us
For questions or to exercise your rights:
10.Payment Processor
Payments are processed by Polar.sh. Their privacy practices are governed by polar.sh/legal/privacy. We encourage you to review it.
Your privacy is our priority. Your words, notes, and files stay with you, always.