A visitor adds a kurta to the cart on your site. A cookie remembers it. The same page also loads an ad tag, a chat widget and an embedded video, and each of those may drop a cookie of its own. Every one of them gets called a cookie, yet browsers and regulators treat them very differently.
The gap between first party vs third party cookies decides what your banner must ask, which tags you can run, and how much of your data survives in each browser. This guide explains the difference in plain terms.
The short answer: who sets the cookie
It all depends on the domain. When the website the visitor is on creates the cookie, it's first-party. When another domain- an ad network, an analytics provider, a video service, a social media service creates the cookie, it's third-party. So the example with the cart was first-party; the ad that loads on the same page and sets its own cookie is not.
The reason we can't always access third-party cookies is that they're tied to their source domain, so the source domain can see all the other domains that are using its cookies. You can only read first-party cookies from your own domain. Here's one more thing: the host site can create its own first-party cookie, but any other third-party code can create a third-party cookie on your page. Hence, you see cookies in a page audit that you never deliberately added.
What first-party cookies do
First-party cookies handle the daily work of a site: sessions, carts, preferences and on-site measurement. The cookie that stores a visitor’s banner choice is also first-party. If a visitor clears their cookies, that choice disappears, and the banner returns to ask again.
They carry less privacy baggage because they avoid the broad cross-site profiling that made third-party cookies contentious. Set up carefully, with defined purposes, minimum data, honoured consent and sensible expiries, they can support GDPR-style rules. But the same source is plain that analytics and personalisation still require consent. First-party does not mean consent-free.
They also stay in one browser, so a customer who browses on a phone and buys on a laptop appears as two separate visitors.
What third-party cookies do
Third-party cookies mostly serve cross-site tracking and advertising. The companies behind them include advertising platforms, agencies and services such as live chat providers. They usually don’t store a name or email address. What they carry is an identifier, and that is enough to link one person’s visits across unrelated sites. This is the practice privacy law is aimed at, and the reason these cookies generally need explicit consent.
What you will find on a typical site
Take an online clothing store. Its first-party cookies keep the cart, remember preferences and save the visitor’s tracking choice. Its third-party cookies come from the tools it has plugged in: an ad pixel, a chat widget, an embedded product video, a social share button. A payment provider’s cookies can also be third-party. The owner wrote none of those third-party cookies, yet they all run on the owner’s pages.
First-party vs third-party cookies, side by side
| First-party | Third-party | |
|---|---|---|
| Set by | The site the visitor is on | Another domain loaded on that page |
| Typical job | Logins, carts, preferences, on-site measurement | Advertising and cross-site tracking |
| Consent | Depends on purpose; essential uses may be exempt | Generally needed |
| Browsers | Allowed, though Safari caps some lifespans | Blocked or restricted in Safari, Firefox and Edge; on by default in Chrome |
How browsers treat each in 2026
Chrome kept third-party cookies on. In April 2025, Google said it would not introduce a separate prompt and would keep its current approach, and users can switch them off in settings. Chrome accounted for 71.37% of browser usage in April 2026, going by the Statcounter figures that piece cites.
Other browsers are less forgiving. Safari, Firefox and Edge already block or restrict third-party cookies, and an August 2026 overview says Safari blocks them by default. Whether a given one runs depends on the browser and on how your site is configured. Some are stopped automatically; others slip through.
First-party cookies get no free pass either. Safari cuts the life of first-party cookies set through JavaScript to seven days. A visitor who returns on day eight can show up in your reports as new. Your numbers will quietly differ by browser.
Three mistakes owners keep making
First-party means no consent. It does not. Consent depends on what the cookie is for. A login or cart cookie is usually exempt, but an analytics or personalisation cookie is not.
Third-party cookies are finished. For most Chrome visitors, they are not, so any ad tag on your site may still be setting them.
Analytics is always first-party. Origin decides, not the tool. One guide lists analytics tools among sources of third-party cookies, while Matomo covers analytics run as first-party cookies. Check which domain actually sets yours.
What the law says about each
Here is the part many owners miss. Consent turns on the purpose of a cookie, not on whether it is first-party or third-party. Under EU law, cookies that aren’t strictly necessary can’t be installed without explicit consent, and that includes a first-party analytics cookie. Scripts should stay blocked before a visitor chooses and after a rejection.
The ePrivacy Directive and the GDPR still apply, and consent must be specific and obtained before cookies are set. Enforcement is live: France’s regulator lists a March 2026 fine of €15,000 on a ticketing company, with cookie consent among the breaches, and it uses an automated crawler to check whether cookies drop before consent.
In India, MeitY notified the DPDP Rules on 13 November 2025. A site using cookies to collect personal data needs valid, specific, informed consent before setting non-essential ones, and the main duties become fully enforceable by 13 May 2027. The cookie-specific reading comes from compliance firms, so confirm it with your lawyer. For the basics behind all this, see our guide on what cookies are.
What to do on your own site
List cookies by domain. Anything not set by your own domain is third-party. Note what each one is for, and who to ask if it needs to be removed.
Judge by purpose, not party. Strictly necessary first-party cookies, such as a login or cart, need no consent but should be disclosed. Analytics, preferences and ads need a yes first.
Block third-party tags until consent. Test it in a private window: reject everything on the banner, reload, and look at which cookies remain.
Build on first-party data. Even with Chrome’s decision, the practical 2026 answer is a mix of authenticated first-party data, server-side measurement, contextual targeting and defensible consent flows. Cookies are only one form of data; when you use data from outside sources, weigh its source, permission, accuracy, ownership and age.
The takeaway
First-party cookies belong to your relationship with a visitor. Third-party cookies belong to someone else’s. Both can need consent, but only one lets a stranger follow your visitor around the web. Know which is which on your site, and most of the compliance work follows. A cookie list you can read aloud in a minute, with a purpose and an owner next to every line, is also the quickest way to find out whether your banner tells visitors the truth. Do that audit once now, and repeat it whenever a new plugin or marketing tag goes live.