This privacy policy applies to the browser extension E Ink Mode. We only process data to the extent necessary to provide functionality and strive to use local storage.

1. Data We Collect and Process

  • Function Settings Data: Theme, language preferences, shortcut settings, font size, line height, font weight, margins, font type, hyperlink behavior, highlight toolbar position, background color, dual-column display, auto full screen, system font size and type preferences, as well as version, policy prompt status, cloud sync toggle, and Focus Timer status.
  • Reading Status Data: Website reading mode activation status, session state within tabs, and necessary cache information.
  • User-Created Content: Highlights, notes, tags, handwritten or drawn strokes, etc. (including corresponding page URLs and titles, with URLs intentionally stripped of any personal identifying information, query parameters, and fragment identifiers to ensure user privacy). Such data for free users is stored only locally; logged-in members can choose to sync it to the cloud (handwriting and drawing sync is not yet supported).
  • Anonymous Analytics Data: Randomly generated installation identifiers and session identifiers, event occurrence domains (only domain names), feature usage events, duration intervals, content length intervals, installation day intervals, extension versions, and necessary debugging flags. This data is used for product quality and feature improvement, helping us understand which features are more useful and can be further enhanced, and which features are not useful and can be removed, allowing for proper allocation of development resources and time, and this data does not contain any information that can directly identify individuals.
  • Device and Language Information: Device type (desktop/mobile), browser and operating system information, language settings, screen resolution, and country codes estimated from the language, allowing us to focus resources on improving the most commonly used device adaptive screens and language presentation effects, this data does not contain any information that can directly identify individuals.
  • Account Data (Logged-in Users): When you choose to log in to your BacInk account, we collect and process your email address and account ID (generated by Supabase authentication service) for identity verification, subscription management, and providing cloud sync functionality. Access tokens and refresh tokens used for verification are stored only in the background service of the extension and are not passed to webpage content scripts.
  • Layout Patch Report Data (when Pro members use the "Patch Layout" feature): Adjustments made to the website layout through the patching tool (website host name, CSS selectors and style adjustments of the adjusted elements), your account ID (for quality management reporting), and extension version. This data is manually reviewed and used to improve the reading experience for all users on that website. Patch settings are stored locally; reporting sharing is enabled by default, and you can turn off the "Help us improve webpage compatibility" toggle on the settings page at any time. After turning it off, the patching function will still work normally, just not upload. The report content does not include full URLs, page content, or any data you input on the webpage.
  • Sharing Data (when you actively use the sharing feature): Shared page URLs, sharing codes, sharing expiration dates, and the highlighted content you choose to share.
  • reMarkable Export Data (when you actively enable it): Device tokens obtained by exchanging reMarkable device codes (stored encrypted locally) and the EPUB file content and titles you actively export, for uploading to your reMarkable account.

2. Data Storage Locations and Methods

  • Mainly stored in the browser extension storage (e.g., chrome.storage) and IndexedDB.
  • Some temporary data (e.g., session identifiers, share cache, and share temporary context) will be stored in session storage (e.g., chrome.storage.session).
  • Cloud Storage (for logged-in members): Function settings, shortcut settings, and highlight data can be synced and stored via BacInk cloud services (Supabase). You can control whether to enable cloud sync on the settings page. The Focus Timer status will also be synced when cloud sync is available. Cloud data is protected by Supabase's Row Level Security, accessible only to you.
  • reMarkable Integration Data: reMarkable device tokens will be stored in encrypted form in the extension's local storage.
  • The current version does not use cookies as the primary storage mechanism.
  • Some data belongs to session data and may reset when the tab is closed or the browser is restarted.

3. Permissions and Uses We Use

  • Storage Permission: Used to save settings, reading status, local notes/highlighting data, share temporary data, reMarkable integration status, and manage authentication sessions.
  • Login Process Tab Control: During the login process, the extension will open and monitor the OAuth authentication tab and automatically close it after verification is complete to finish the login process.
  • Website Content Access: To provide reading mode, highlighting, and handwriting features, the extension will execute content scripts on qualifying website pages, analyzing and rearranging page content locally; this processing will not upload the entire page content to the server by default.
  • Network Host Access Permission: Only used for the following services: https://www.google-analytics.com/, https://bacink.com/ , endpoints used by BacInk cloud services (including authentication, settings sync, Focus Timer sync, and sharing services), and endpoints used for reMarkable services when you actively enable them.

4. Data Transmission to External Parties

  • Google Analytics 4 (GA4): Sends anonymous event data (such as feature usage counts, mode switches, page navigation, theme switches, time intervals, and domain names) for product quality and feature improvement.
  • BacInk API: Requests article summary data needed to update messages and privacy policy links from https://bacink.com/backend/api/blog.php.
  • Layout Patch Reports (Pro members, can be turned off): When you use the "Patch Layout" feature and do not turn off the "Help us improve webpage compatibility" toggle, your patch content (website host name and layout adjustment items) will be sent to the BacInk server for manual review. This transmission is protected by HTTPS encryption and has a monthly upload limit.
  • BacInk Cloud Services (Supabase): For logged-in members, after enabling cloud sync, extension settings (margins, fonts, line heights, shortcuts, etc.), highlights and notes, and Focus Timer status will be sent to BacInk's Supabase backend for storage and cross-device sync. This transmission is protected by HTTPS encryption, and data is only associated with verified accounts.
  • Sharing Function (Supabase): When you actively create a sharing link, the system will upload the necessary data for sharing (such as page URLs and highlighted content) for invitees to view the shared content.
  • Google OAuth Authentication: If you choose to log in with your Google account, the login process will open Google's OAuth authorization page. BacInk only receives the session token provided by Supabase after verification is complete and does not directly obtain your Google password.
  • reMarkable Cloud Services (when you actively enable it): When you actively set up reMarkable integration and execute exports, the system will send the EPUB content and document titles you specify to reMarkable cloud services.

5. What We Will Not Do

  • We do not actively collect data that can directly identify individuals, such as names or phone numbers (email addresses are only collected when you actively log in).
  • We do not send complete browsing URLs, URL paths, or query parameters; only the page host names (e.g., example.com) are recorded in the analytics data, excluding paths or personalized information.
  • We will not send your account passwords or form input content from the webpage to the BacInk server.
  • We will not sell your personal data.
  • We will not upload your highlights, notes, or handwritten content to the server without your consent. The cloud sync feature must be actively logged in and enabled by you, and such data for free users will always remain local.
  • We will not transmit access tokens (access token, refresh token) to any webpage content scripts or third-party services.
  • We will not automatically export content to reMarkable cloud services without your active operation.

6. Data Retention and Deletion

  • Local data will be retained in your browser until you clear browser/extension data or remove the extension.
  • Remote analytics data is managed by Google Analytics according to its service policies and retention settings.
  • Cloud sync and sharing data (settings, shortcuts, highlights, Focus Timer status, and content you actively create for sharing) are managed by BacInk cloud services. You can delete your account and cloud data through the account management page on the official website.
  • The reMarkable device token can be unlinked and cleared by you in the extension.

7. Your Control

  • You can control local data retention and related functionality by clearing browser data, removing the extension, and adjusting browser permissions.
  • You can enable or disable the cloud sync feature at any time on the settings page.
  • You can turn off the "Help us improve webpage compatibility" toggle at any time on the settings page to stop uploading layout patch reports, and you can remove all your patch settings on specific websites using the reset button on the patching toolbar.
  • You can terminate your account session using the logout feature in the control panel, and after logging out, the extension will revert to local storage mode.
  • You can delete local highlights, notes, and handwritten data, or revoke the sharing links you created.
  • You can unlink reMarkable in the extension and clear the device token.
  • You can delete your account on the official website's account management page to remove personal data stored in BacInk cloud services and all data related to that account.

8. Policy Updates

This policy may be updated due to feature or regulatory requirements, and updates will be published on this page along with adjustments to the "Last Updated" date.

9. Contact Us

If you have any questions about this privacy policy, please contact: contact@bacink.com

Using E Ink Mode indicates that you have read and agree to this privacy policy.

Last updated: July 16, 2026