Global Privacy Control (GPC) — a browser-level header and JavaScript signal that lets users automatically opt out of personal data sale or sharing without manually clicking opt-out links on every site they visit.

Detected via:

if (navigator.globalPrivacyControl === true) {
  // honour the opt-out
}

Or via the Sec-GPC: 1 HTTP request header.

California's CPRA explicitly requires sites to honour GPC as a valid opt-out signal. Failing to honour it has been the subject of CPPA enforcement actions since 2023.

GPC is currently active in:

DuckDuckGo browser (default on)
Brave browser (default on)
Firefox (with Privacy Badger extension or about:config flag)
Chrome / Edge (via Privacy Badger or DuckDuckGo Privacy Essentials extensions)

Most cookie banners on Shopify do not honour GPC. Consentico does — for California visitors with GPC active, the banner auto-applies the opt-out before the visitor interacts.

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