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

1. Data We Collect and Process

  • Function Settings: Preferences such as theme, language, shortcut settings, font size, line height, font weight, margins, font, hyperlink behavior, position of highlight toolbar, background color, two-column display, auto full screen, system font size and font type, as well as version and policy notification status.
  • Reading Status Data: Status of website reading mode, session status within tabs, and necessary cache information.
  • User-Generated Content: Data such as highlights, notes, tags, handwriting or drawing strokes (including corresponding page URLs and titles, with URLs stripped of any personally identifiable information, query parameters, and fragment identifiers to ensure user privacy). For free users, this data is stored locally only; logged-in members can choose to sync it to the cloud (handwriting and drawing sync feature is not yet supported).
  • Anonymous Analytics Data: Randomly generated installation identifiers and session identifiers, event occurrence domains (domain names only), functional usage events, time spent intervals, content length intervals, extension versions, and necessary debugging flags. This data is used for product quality and feature improvement, helping us understand which features are useful to enhance further and which can be removed to allocate development resources and time efficiently. None of the above data contains 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 code inferred from the language. This allows us to focus resources on improving the adaptive display for the most commonly used devices and language presentation effects. None of the above data contains any information that can directly identify individuals.
  • Account Data (for logged-in users): When you choose to log into your BacInk account, we collect and process your email address and account ID (generated by Supabase authentication service) to identify your identity, manage subscription plans, and provide cloud sync functionality. The access token and refresh token used for authentication are stored only in the background service of the extension and are not passed to web content scripts.
  • Sharing Data (when you actively use the sharing feature): Shared page URLs, share codes, share validity periods, and the highlights you choose to share.

2. Data Storage Locations and Methods

  • Primarily stored in the browser extension storage (e.g., chrome.storage) and IndexedDB.
  • Some temporary data (e.g., session identifiers and share cache) will be stored in session storage (e.g., chrome.storage.session).
  • Cloud Storage (for logged-in members): Functional settings, shortcut settings, and highlight data can be synced and stored via BacInk cloud services (Supabase). You can control whether to enable cloud syncing in the settings page. Cloud data is protected by Supabase's Row Level Security and is accessible only to you.
  • Current version does not use cookies as the primary storage mechanism.
  • Some data belongs to session data and may be reset upon closing tabs or restarting the browser.

3. Permissions and Uses

  • Storage Permission: Used to save settings, reading status, and local notes/highlighting data, as well as manage authentication sessions.
  • Tabs Permission: Used to open and monitor the OAuth authentication tab during the login process and automatically close it once authentication is complete.
  • Website Content Access: To provide reading mode, highlights, and handwriting features, the extension executes content scripts on eligible website pages, analyzing and rearranging page content locally; this process does not upload the entire page content to the server by default.
  • Network Host Access: Used only for the following services: https://www.google-analytics.com/, https://bacink.com/, and Supabase endpoints used by BacInk cloud services (including authentication, settings synchronization, and sharing services).

4. Data Transmission Outside

  • Google Analytics 4 (GA4): Transmits anonymous event data (e.g., number of feature uses, mode switching, page navigation, theme switching, time intervals, and domain names) for product quality and feature improvement.
  • BacInk API: Requests article summary data needed to update news and privacy policy links from https://bacink.com/backend/api/blog.php.
  • BacInk Cloud Service (Supabase): For logged-in members who enable cloud sync, extension settings (margins, fonts, line heights, shortcuts, etc.), highlights, and note data will be transmitted to BacInk's Supabase backend for storage and cross-device synchronization. This transmission is protected by HTTPS encryption and is only associated with authenticated accounts.
  • Sharing Function (Supabase): When you actively create a share link, the system will upload data needed for sharing (such as page URLs and shared highlights) 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 authentication is complete and does not directly obtain your Google password.

5. What We Won't Do

  • We do not actively collect personal data that can directly identify individuals, such as names or phone numbers (email addresses are only collected when you log in).
  • We do not send complete browsing URLs, URL paths, or query parameters; analysis data only records the page host name (e.g., example.com) without including paths or personal information.
  • We will not send your account passwords or form input content in webpages to the BacInk server.
  • We will not sell your personal data.
  • We will not upload your highlights, notes, or handwriting content to the server without your consent. The cloud sync function requires you to log in and enable it; for free users, such data is always retained locally.
  • We will not pass access tokens or refresh tokens to any web content scripts or third-party services.

6. Data Retention and Deletion

  • Local data will be retained in your browser until you clear browser/extension data or remove the extension.
  • Remote analytic data is managed by Google Analytics according to its service policy and retention settings.
  • Cloud sync and sharing data (settings, shortcuts, highlights, 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.

7. Your Control Rights

  • You can control the 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 in the settings page.
  • You can terminate your account session using the logout function in the control panel. After logging out, the extension will revert to local storage mode.
  • You can delete local highlights, notes, and handwriting data, or revoke the share links you created.
  • You can delete your account on the account management page of the official website to remove personal data stored in BacInk cloud services and all related account data.

8. Policy Updates

This policy may be updated due to functional or regulatory requirements. Updates will be published on this page and the "Last Updated" date will be adjusted accordingly.

9. Contact Us

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

By using Eink Mode, you acknowledge that you have read and agreed to this privacy policy.

Last updated: May 3, 2026