First-party cookie vs third-party cookie: our complete guide

The internet is an integral part of daily life. For many people, browsing the web is a routine activity — in France, people spend an average of about 2 hours and 18 minutes online each day. Every site visited collects information about our activity using what are known as cookies. Their use often raises questions about privacy and security.

First-party cookies

What is a first-party cookie?

First, let’s recall what a cookie is. A cookie is a small file stored on a user’s computer, tablet, or smartphone. Associated with a domain like www.example.com, this file is automatically sent back when the same user returns to that site.

A first-party cookie, also called an “internal,” “native,” or “first-party” cookie, is placed directly by the site owner on the domain the user is visiting.

This type of cookie can be used to:

ensure proper functioning of the website;
collect personal data;
track user behaviour;
serve advertising purposes.

It is created the first time a user visits an online shop or a showcase website.

Examples of first-party cookies

Session cookies

On the web, sessions are a common way to store data in a browser. Session cookies hold information about a user’s visit, such as items added to a cart or a partially filled-in form. Even when the user moves between pages, this information stays accessible.

They only exist while the individual session is active and are not saved for future use. Session cookies support basic website functionality.

Preference or personalization cookies

These collect information about a user’s choices and preferences. The purpose is to differentiate users’ online experiences based on their profile. Preference cookies can change how a site behaves or appears, adapting it to various parameters.

Examples include:

language;
location;
device type;
referring site;
date of last visit;
recently watched videos;
history of pages visited.

Authentication cookies

These allow users to access their account using previously stored credentials.

Advantages of first-party cookies

Main strengths of first-party cookies in your marketing strategy:

personalization of user experience;
improved website functionality;
access to secure areas of the site;
temporary information storage;
better control of data (full ownership);
less intrusive in terms of user privacy;
smoother navigation;
more relevant advertising.

Used responsibly, first-party data helps build direct relationships with your audience and improve advertising performance.

Third-party cookies

What is a third-party cookie?

A third-party cookie is stored on domains other than the one the user is currently visiting. They are usually managed by third parties that the visited site has asked to load, not by the user’s site.

Third-party cookies allow those third parties to gather statistics about the pages users visit. They are often used for advertising purposes such as retargeting and ad serving.

Users can block third-party cookies through private browsing modes, certain browsers like Safari or Tor, or ad-filtering software.

Examples of third-party cookies

Advertising cookies

Advertising cookies are mostly used to manage ads, their content, and frequency. They determine which ad to show based on recent browsing. They also help control how many times a user sees an ad and measure campaign performance.

Social sharing cookies

These are essential for connecting with social platforms. They are often generated by social share buttons and managed by the social network.

Behavioural or audience-measurement cookies

Behavioural analytics cookies track user browsing across websites or apps. They can generate heat maps or screen recordings. The goal is to create profile types to identify interests and serve targeted ads.

Audience measurement cookies provide brands with traffic statistics about elements of a site or app.

Advantages of third-party cookies

Key benefits of third-party cookies:

targeted advertising;
audience measurement;
data analysis;
integration of third-party services;
behavioural targeting;
contextual advertising;
ad control mechanisms (capping, fraud prevention).

Difference between first-party and third-party cookies

The key difference is who places the cookie in the browser:

a first-party cookie is generated by the site the user is visiting;
a third-party cookie is placed by another site on the user’s device.

Comparison table

First-party cookie

Creation: set by the domain currently open in the browser
Accessibility: only works on the main domain
Browser support: supported by all browsers (though users can block them)

Third-party cookie

Creation: set by servers such as ad servers on the publisher’s site
Accessibility: accessible on any site loading third-party code
Browser support: many browsers now block them due to privacy concerns

Rules for cookies and other trackers

Key regulatory principles:

clearly inform users of the purposes of cookies;
provide simple refusal mechanisms;
require explicit consent for non-essential cookies.

Silence or inactivity is considered refusal.

Good to know: how to prove user consent

Several methods can be used:

storing the cookie-consent code in escrow;
publishing a dated hash of the code;
capturing dated screenshots of consent interfaces;
regular third-party audits;
archiving CMP configuration data.

Planned removal of third-party cookies in 2024 by Google

Google has announced the discontinuation of third-party cookies in Chrome (initially planned for Q3 2024, previously postponed).

Key impacts:

shift from one dominant solution to multiple methods;
move toward delayed feedback;
transition from deterministic to probabilistic models;
increased use of aggregated data.

Cookieless alternatives and future strategies

For effective cookie management, it’s essential to understand the difference between first-party and third-party cookies. While third-party cookies are being phased out, first-party cookies remain central.

Dataventure offers cookieless solutions including: