What are third-party cookies?
Third-party cookies are files stored in your browser by a player other than the site you are visiting, almost always an ad platform. Read again from page to page, they rebuild your browsing trail to target ads, unlike first-party cookies, which handle your cart or your session. The topic continues in chapter 2 of my book, Vivre sans Google.
Information verified on July 13, 2026
A cookie is a small file a site stores in your browser to remember you. When it comes from the site you are visiting, it is rather useful: it keeps your cart, your open session, your language. A third-party cookie is planted by another player, invisible on the page, almost always an ad platform.
Picture a badge the same advertiser sticks on your back, site after site. You read an article, compare flights, stop by a health forum: the badge is read again on every page where that platform is present. Put end to end, those visits rebuild your entire browsing trail. Ever wondered why a pair of shoes follows you around for two weeks? That is the badge.
Their decline has been announced for years, under pressure from regulators and from browsers that block them by default. The tracking does not stop, though: other techniques are already taking over, like fingerprinting, which recognizes your browser by its settings without storing anything at all.
Where it plays out: chapter 2 of the book tackles the browser, the first observation post, the leaving Chrome guide walks you through switching, and the Web browsers category compares those that block these cookies out of the box.
This topic is chapter 2 of my book
It answers these questions, among others:
- which settings actually make a difference once the browser is installed?
- how do you handle the work computer where Chrome is required?
- and how do Safari and Edge hold up, the ones nobody ever compares?
Forthcoming 22/10/2026 from Éditions Eyrolles
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Tech jargon, translated
Every week in The Spark, I break down one tech story through the privacy lens. And what you can do about it, concretely.
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