Anti-Tracking Guide

Global Privacy Control and California

What California's privacy agency says about GPC as an opt-out signal, and its 2025 sweep with three state Attorneys General on honoring it.

Official source: California Privacy Protection Agency, Joint Investigative Privacy Sweep (9 September 2025). Verified on

1 min read · Review scheduled for 2027-01-24

Contents

In short

  • GPC is a browser setting or extension that tells websites automatically that you do not want your data sold or shared, so you do not have to opt out site by site (CPPA).
  • California calls it an opt-out preference signal. The alternative is to use each business's "Do Not Sell or Share" link.
  • On 9 September 2025 the California Privacy Protection Agency, with the Attorneys General of California, Colorado and Connecticut, announced a joint sweep. It checks whether businesses honor opt-outs sent through GPC and asks those that do not to comply.

If you live in one of these states

If you live in California, Colorado or Connecticut, turning on GPC is a way to send an opt-out with every request. Mozilla explains how to turn it on in Firefox and its limits: it is a request, not a block (Mozilla). Steps for every browser are on how to turn on Global Privacy Control.

What it does not do

  • It does not stop fingerprinting or hide your IP address.
  • It works only on sites that read it and are bound by a law that requires them to.
  • A site can ignore it. The sweep exists because some do.

Limits

We read the announcement and nothing else from the agency. We did not read the regulations or the 2026 rulemaking papers that came up in our search, and we did not check the rules of other states. A lawyer can say what binds a given business.

Keep reading: EU rules on tracking

Outside this page: The results of the sweep, which the announcement does not give.