TCP will be available in the latest version of Firefox, although it seems unclear how users will be able to verify if the feature is enabled. However, Erwin also noted that Firefox users on iOS won’t be able to use TCP, citing Apple’s restriction that forces iOS web browsers to use the WebKit browser engine (the same one used by Safari). TCP is available on ‘Firefox Focus,’ a version of mobile Firefox that’s all about privacy. Mozilla’s chief security officer, Marshall Erwin, told The Verge that there’s a different timeline for bringing TCP to Firefox on Android. Notably, mobile versions of the Firefox browser don’t have TCP - at least, for now. Unfortunately, not all Firefox users will have TCP. Today’s announcement will shift the feature from opt-in to on-by-default, which is a big step forward. TCP was first made available in Firefox back in May as an opt-in feature while Mozilla tested it. Apple’s Safari also offers ‘Intelligent Tracking Prevention’ that helps prevent cross-site tracking. Google previously announced plans to phase out third-party cookies in Chrome but has delayed the move until 2023. However, Firefox isn’t the only browser taking on third-party cookies. Mozilla says that TCP helps prevent the worst privacy problems of third-party cookies while also allowing those cookies to fulfill some less invasive use cases, such as analytics. No other websites can reach into the cookie jars that don’t belong to them and find out what the other websites’ cookies know about you - giving you freedom from invasive ads and reducing the amount of information companies gather about you.”

“Any time a website, or third-party content embedded in a website, deposits a cookie in your browser, that cookie is confined to the cookie jar assigned to only that website.

This approach to cookies makes it more difficult for trackers to link user activity across websites: Mozilla describes the feature as giving each website its own cookie jar, rather than letting websites share one giant cookie jar (check the illustration above). In a blog post about the feature, Mozilla detailed how TCP will improve user privacy by confining cookies to the website that created them. Mozilla announced that it will start rolling out its ‘Total Cookie Protection’ (TCP) feature by default to all desktop Firefox users worldwide.

Enable cookies mozilla firefox browser