Privacy Policy: X-Filter

Effective date: May 5, 2026

Overview

X-Filter is a browser extension that helps you control what appears in your X.com (formerly Twitter) feed. This privacy policy explains how this extension manages data.

Data Collection

X-Filter does not collect, transmit, or share any personal data with external servers. All processing occurs entirely within your browser. No data is sent to the developer, X.com, or any third party.

Information accessed from the page

While you browse X.com, the extension accesses the following data from the page to provide its filtering functionality:

Data Accessed Purpose Retention
X.com timeline API responses (via XHR interception) Extract post identifiers and post types (repost, quote, reply, media) for filtering Held in memory only
X.com Redux state (via React Fiber traversal) Access navigation state, user ID, and notification counts for panel features Held in memory only
twid cookie Extract your numeric user ID to scope filtering to your account Held in memory only
X.com list API responses Detect list subscribe/unsubscribe events to keep your list navigation up to date List metadata stored locally (see below)

The extension uses window.postMessage with window.location.origin (not "*") for internal communication between its components, preventing cross-origin data leakage.

Information stored locally

The extension stores the following data in your browser’s local storage (chrome.storage.local):

  • Filter preferences (e.g., hide reposts, hide media)
  • Seen-post timestamps (auto-deleted after 24 hours)
  • X.com list metadata (list IDs, names)
  • Navigation visibility and ordering preferences
  • Last read changelog version

All data persists until you uninstall the extension or manually clear storage.

Information processed in memory

While you browse X.com, the extension temporarily processes:

  • Tweet/post metadata extracted from X.com’s GraphQL API responses
  • Post classification data (repost, quote, reply, media, profile)
  • Session metrics (post counts, filter counts)

This metadata is held in memory only, bounded by internal limits (max 3000–5000 entries), and is never transmitted outside your browser.

Data Usage

All data is used solely to provide the extension’s core functionality:

  • Applying your chosen filters to the X.com feed
  • Displaying filter counters and seen-post indicators
  • Persisting your settings, list data, and navigation preferences across browser sessions
  • Providing a custom navigation rail with your X.com lists

Third Parties

X-Filter does not integrate with any third-party services, analytics platforms, or advertising networks. No data is shared with X.com, the developer, or any other party.

Data Security

Because all data remains on your local device, it is protected by your operating system’s and browser’s built-in security mechanisms. The extension does not request permissions to access websites other than X.com domains (x.com, www.x.com, mobile.x.com).

Viewing Your Stored Data

You can view all data stored by X-Filter at any time:

  1. Open X.com in your browser
  2. Open Chrome DevTools (F12 or Ctrl+Shift+I / Cmd+Option+I)
  3. Go to the Application tab
  4. In the left sidebar, expand Storage → Local extension storage
  5. Select X-Filter (or the extension ID)
  6. You will see all stored keys and their values

Your Rights and Control

You may clear all stored data at any time by:

  • Uninstalling the extension
  • Using your browser’s extension storage clearing features (see “Viewing Your Stored Data” above)
  • Toggling filters off, which stops further processing

Changes to This Policy

If this privacy policy changes, the updated version will be made available at the same URL. Continued use of the extension after any changes constitutes acceptance of the revised policy.

Contact

If you have questions about this privacy policy or the extension’s data practices, please contact the developer at: dev@digitalsun.cc

X-Filter is an independent project and is not affiliated with X Corp.