Understanding and Enabling Global Privacy Control in Firefox

This article provides a comprehensive overview of the Global Privacy Control (GPC) HTTP signal and explains how you can use it to protect your online data. You will learn what the GPC signal is, how it legally compels websites to respect your privacy, and the exact steps required to enable this feature within the Mozilla Firefox web browser using both the standard settings menu and the advanced configuration page.

What is the Global Privacy Control (GPC) HTTP Signal?

Global Privacy Control (GPC) is a technical specification designed to automatically communicate your privacy preferences to the websites you visit. When enabled, your browser sends a specific HTTP header (Sec-GPC: 1) along with your regular web traffic. This signal serves as a universal opt-out mechanism, instructing websites not to sell or share your personal data with third-party advertisers or data brokers.

GPC is the spiritual successor to the older "Do Not Track" (DNT) signal. While DNT failed because websites were not legally required to honor it, GPC has legal backing. Under privacy laws such as the California Consumer Privacy Act (CCPA), the California Privacy Rights Act (CPRA), and regulations in several other states and countries, businesses are legally required to recognize and respect the GPC signal as a valid consumer opt-out request.

How to Enable GPC in Firefox (Standard Method)

Mozilla introduced a built-in toggle for GPC starting in Firefox version 120. If your browser is up to date, you can enable the signal directly through the main settings menu by following these steps:

  1. Open the Firefox browser.
  2. Click the menu button (three horizontal lines) located in the top-right corner of the window.
  3. Select Settings from the dropdown menu.
  4. Click on Privacy & Security in the left-hand navigation pane.
  5. Scroll down until you find the Website Privacy Preferences section.
  6. Check the box next to Tell websites not to sell or share my data.

Once checked, Firefox will immediately begin broadcasting the GPC HTTP signal to every website you visit.

How to Enable GPC in Firefox (Advanced Method)

If you are using an older version of Firefox or prefer using the advanced configuration menu, you can manually activate the GPC signal through the about:config page:

  1. Open a new tab in Firefox.
  2. Type about:config into the address bar and press Enter.
  3. A warning page may appear. Click the Accept the Risk and Continue button to proceed.
  4. In the "Search preference name" bar at the top, type privacy.globalprivacycontrol.enabled.
  5. Locate the preference in the results below. If it is set to false, click the toggle icon on the far right (or double-click the row) to change the value to true.
  6. Next, search for privacy.globalprivacycontrol.functionality.enabled in the same search bar.
  7. Ensure this value is also set to true by clicking the toggle icon if necessary.

Once both values are set to true, the configuration is complete. You can close the tab, and Firefox will actively transmit the GPC signal during your browsing sessions.