Firefox Partitions All Cookies by Default

What Changed

On June 14, 2022, Mozilla began rolling out Total Cookie Protection by default to Firefox desktop users worldwide.^1,2

Total Cookie Protection gives each website its own "cookie jar". Any cookie set by a site, or by third-party content embedded in it, is confined to that site's jar. Another site can't read it, even if the same third party is embedded on both. A tracker embedded across many sites ends up with a separate, unconnected cookie on each one.¹

Firefox's earlier Enhanced Tracking Protection blocked cookies from a list of known trackers. Total Cookie Protection applies to all third-party cookies, whether or not the company is on a list.¹

Two weeks later, Firefox 102 added a defence against a different technique: tracking parameters added to links. With Enhanced Tracking Protection set to strict, Firefox began removing known tracking parameters from URLs as people navigate, including Facebook's fbclid click ID and the email-tracking parameters used by HubSpot and Marketo.^3,4 It wasn't on by default, but it showed where browsers would go next once cookies stopped working: Apple took the same approach with Link Tracking Protection in 2023.

Why It Mattered

Partitioning is a different approach from Safari's outright blocking. Third-party cookies still work inside each site, so embedded content like video players, chat widgets and payment forms keeps working, but they can no longer follow a person from one site to another.¹

Partitioning has since become a common pattern. Chrome supports a version of it through CHIPS, one of the few Privacy Sandbox technologies Google kept when it retired most of the rest in 2025.⁵

For cross-site tracking, the result in Firefox is similar to blocking: a third party can't build a profile of someone across sites with cookies. As with Enhanced Tracking Protection, Firefox's small share of browsing limited the direct effect on most advertisers' reach.