first-party adat

in English: first-party data

basicwidespread

Data that a company collects directly from its own customers and visitors on its own platforms, rather than buying or receiving it from others.

In plain terms

First-party data is what a company knows about you from its own relationships: what you bought in its webshop, what you clicked in its newsletter, and what you asked its customer service. No one stands between you; the data is generated where you and the company meet.

It is like the corner baker who has served you for years: they know you take a chocolate swirl bun on Fridays and set one aside for you. They do not know this from a data broker, but from knowing their customers. Third-party data, by contrast, is when an outside company sells a list about who in the neighborhood likes bakery pastries.

It became important because several browsers (such as Safari and Firefox) now limit cross-site tracking by default, and data protection rules have tightened. What remains certain for the company is its own data. This is why it is generally more accurate and up-to-date than purchased data, and easier to verify its origin.

In the AI era it is worth even more: recommendation systems learn from it, and it is what an AI agent works from when it answers you on the company's behalf or puts together a personalized offer.

How it works

Collection: the company records what happens on its own platforms, meaning its website, app, store, newsletter, customer service, and loyalty program.
Legal basis and consent: processing personal data requires a legal basis. This can be, for example, the performance of a contract, but consent is required for cookies that are not strictly necessary and for many marketing purposes. This is why you see cookie banners, privacy notices, and subscription checkboxes.
Linking: data from various sources is organized into a customer profile, typically in a CRM or customer data platform (CDP).
Use: profiles are used to segment people into groups, personalize offers, ads and newsletters, or to feed an AI model or agent.
Measurement and maintenance: they check what worked, delete outdated data, and fulfill your access or deletion request.

An everyday example

You order running shoes from an online shop, and three months later you receive an email from them about running socks and an upcoming race. They did not follow you around the internet: they saw in their own system what you bought from them and inferred from that.

Who is affected

marketerWith the decline of third-party cookies, first-party data has become the most reliable basis for targeting, personalization, and measurement. → Marketing

entrepreneur, executiveYour own customer data is an asset that competitors cannot buy, and it reduces dependence on the big advertising platforms.

developerIt must build the collection, consent management, and the secure data layer that AI agents access. → Code

everyoneWith every registration, purchase, and loyalty card, you provide such data, and you have the right to know how it is used.

A common misconception

MythFirst-party data can be used freely by the company without permission, as it belongs to them.

In realityPersonal data is subject to the GDPR in the same way: it requires a legal basis, a clear purpose and information for the person concerned. The legal basis is not always your consent, but even then the company cannot use the data for just any purpose. You can also request access to your data or its deletion.

Limits and risks

It only shows what you do on the company's own platforms, so it reveals little about your interests elsewhere or about those who are not yet customers.
At small companies, little data is collected, so conclusions drawn from it can easily be misleading.
Poorly maintained, outdated, or duplicated data leads to bad recommendations and incorrect AI responses.
The more data a company stores, the greater the damage in case of a data leak and the greater its responsibility.

Similar, but not the same

third-party adat – This is collected by an external party from many sources and sold, so the company has no direct contact with the people it concerns.
zero-party adat – You provide this consciously, for example in a questionnaire or settings, while most first-party data comes from observing your behavior.
second-party adat – This is another company's first-party data, shared directly based on a partnership agreement.

Related concepts

Broader

customer data, data-driven marketing, data protection

Narrower

first-party cookie, purchase history, CRM-adat

On the edge

zero-party adat, third-party adat, customer data platform, personalization, consent management

A brief history

The term originates from the online advertising industry. It grew out of the distinction between first-party and third-party cookies. It truly came into the spotlight following the application of the GDPR in 2018 and browser tracking restrictions (Safari, Firefox). It intensified even more in January 2020, when Google announced it would phase out third-party cookies in Chrome. Google stepped back from this plan in 2024, and in 2025 it also discontinued the Privacy Sandbox program intended to replace them. Despite this, the shift towards first-party data has remained.

Where things stand

By the end of 2026, first-party data has become a cornerstone of digital marketing, with many companies basing targeting and measurement primarily on it. The new direction is to use it to feed their own AI systems and agents.

Status: 2026 November

In the news

Appears in 1 Agent Age stories; the curve shows weekly occurrence in the news magazine.

AI agents help publishers monetize first-party dataAug 3, 2026 · Marketing

Also known as

first-party data · first party adat · 1st party data · 1P data · 1P adat · first-party data · first-party data · first-party customer data

Sources

HTTP cookie – Wikipedia

This entry was machine-edited and has undergone machine expert review; the “In the news” section updates automatically from Agent Age stories.