Anti-Tracking Guide

Global Privacy Control (GPC): what it is

What the Global Privacy Control signal asks sites to do, how a site receives it, where it has legal weight and why it is a request, not a block.

Official source: Mozilla Support, Global Privacy Control. Verified on

2 min read · Review scheduled for 2027-01-19

Contents

What it is

Global Privacy Control (GPC) is a browser setting, available in Firefox since version 120, that tells websites not to sell or share information about your browsing on that site (Mozilla). The GPC project describes it as a proposed specification that lets a browser or extension send your preference automatically, so you do not have to opt out site by site. It is being standardised at the W3C (GPC).

Who supports it

The GPC site lists Brave, the DuckDuckGo browser, Firefox, Disconnect, Privacy Badger, OptMeowt and lockrMail. Brave and DuckDuckGo have it built in; Firefox offers it as a setting (GPC).

How a site receives it

The signal travels two ways: as the Sec-GPC header on every request to a server, and as navigator.globalPrivacyControl for scripts on the page. The property is true when you have opted out, and false when you have expressed no preference (MDN). Our browser check reads that property, so you can see what sites see.

GPC works as a "Do Not Sell" mechanism in some US states, including California, Colorado and Connecticut. Mozilla's page also names the EU, UK, Nevada, Utah and Virginia, and says GPC has stronger recognition under laws such as the CCPA and GDPR. Outside certain regions, sites can choose whether to comply (Mozilla).

Limits

  • It is a signal, not a blocker. Some websites may ignore it.
  • It does not stop all tracking. Mozilla suggests combining it with Enhanced Tracking Protection.
  • It is not a replacement for Do Not Track, which Firefox removed in version 135 (Mozilla).

Turning it on

Brave and the DuckDuckGo browser send it by default, Firefox has an off-by-default setting, and Chrome, Edge and Safari need an extension. Steps for each, and how to confirm it worked, are on how to turn on Global Privacy Control.

Keep reading: Global Privacy Control and California law · Browsers compared · Tracking parameters