First-party data

What it means

First-party data are data a company collects directly from its customers and visitors, for example from orders, sign-ups, its newsletter, customer support or its own web analytics. The company knows where they came from and for what purpose they were obtained.

They differ from third-party data, which a company buys or obtains through ad networks and other domains' cookies. As browsers restrict third-party cookies and regulation tightens, first-party data are becoming ever more valuable for marketing and measurement.

They are typically gathered in a CRM or a customer data platform, where purchases, e-mail clicks and on-site behaviour are combined. From them come segments for personalised campaigns and lookalike audiences in ad platforms.

How it works in practice

Companies collect first-party data by offering value in exchange: a loyalty programme, a sign-up discount, useful content or a calculator. The clearer the benefit to the customer, the more willingly they share data and the more accurate the data are.

For measurement, server-side tracking is spreading, where events are sent from the company's server rather than directly from the browser to ad platforms. The company has better control over what data leave, but it still needs user consent.

Reliable data need order: consistent customer IDs, deduplication and regular removal of inactive contacts. Poor data quality shows up as inaccurate targeting and needlessly high costs for e-mail tools.

What to watch out for

First-party data must also be collected in line with the GDPR and cookie rules. They need a legal basis, information about the purpose and, for marketing, often consent; having collected the data yourself does not mean you may use them for anything.

Uploading customer e-mail addresses to ad platforms to build audiences is a transfer of personal data. It must be disclosed in the privacy notice, covered by a processor agreement and assessed for transfers outside the EU, or the supervisory authority may impose a penalty.