Last updated: July 24, 2026

Tracker Blocker by Opt Out Rights is designed to process browsing activity locally in Firefox. Opt Out Rights does not collect, receive, sell, share, or transmit browsing activity, tracker matches, saved rules, or extension diagnostics during normal use.


To block and explain requests, the extension observes page and subresource request information available through Firefox's extension APIs. Classification uses a conservative tracker catalog, EasyPrivacy network rules, and explanations packaged inside the extension. Normal use does not contact a remote classification service, download filter updates, or load remote code.

The extension stores:

• always-paused sites, site-specific hostname allows, and global hostname overrides in browser.storage.local until you remove or reset them;
• pause-once state in browser.storage.session for the current browser session;
• a minimal per-document ledger containing Firefox's opaque document identifier and a blocked-request count in session storage; and
• bounded request evidence in background-process memory so the popup can explain recent activity.

Detailed request evidence is not written to durable storage. In-memory evidence is discarded when Firefox terminates the extension background process. Session state is discarded by Firefox with the applicable session or tab. Durable settings remain until the user removes them, resets saved rules, uninstalls the extension, or clears extension data.


Tracker Blocker has no extension account, analytics, telemetry, advertising, cloud synchronization, or sale of data. It does not transmit the locally processed data to Opt Out Rights or third parties during normal use.


Users can review and remove saved rules in Tracker Blocker Settings, reset all saved rules, or uninstall the extension. When reporting breakage or a false positive, users should provide only the minimum public hostname and reproduction steps needed and should not send private URLs, credentials, account data, or browsing history.


Support URL: https://github.com/OptOutRights/tracker-blocker/issues

Privacy/security email: trackerblocker@optoutrights.org