The essentials
- Definition: first-party data is information collected directly by a company from its visitors, prospects and customers, with their consent.
- Sources: forms, customer accounts, purchases, emails, calls, loyalty programmes, surveys, and behaviour on your site and app.
- Uses: customer lists for advertising, lookalike audiences, exclusions, personalisation, email segmentation, offline conversion measurement.
- What is at stake in 2026: with third-party cookies eroding, it is the only durable data; its value depends on its freshness, its completeness and the consent collected.
Enhanced measurement first-party data (first-party data) means all the information a company collects directly from its visitors, prospects and customers, on its own channels: website, app, shop, customer service, emails. It stands in contrast to third-party data, bought or inherited from advertising platforms, whose availability is closing off with the disappearance of third-party cookies. It is today a company's most durable marketing asset, because it belongs to the company and depends on no browser.
The sources of first-party data
| Source | Data obtained | Value |
|---|---|---|
| Customer account and orders | Identity, purchase history, average basket, frequency | The highest: it makes lifetime value and repeat purchase possible |
| Forms (quote, contact, download) | Email address, company, stated need | High in B2B, the basis of the CRM |
| Newsletter and emails | Address, interests, engagement | A direct channel with no intermediary |
| Behaviour on the site | Pages viewed, products browsed, funnel steps | Useful for personalisation and audiences |
| Calls and customer service | Reason for contact, objections, satisfaction | Under-used, and rich material for your messaging |
| Surveys and reviews | Motivations, barriers, ratings | Complements declared data |
| Loyalty programme | A unique identifier online and in store | Connects physical and digital journeys |
What it makes possible in advertising and marketing
- Customer lists: imported as hashed addresses into Google Ads, Meta or LinkedIn, they serve to retarget, to exclude existing customers from an acquisition campaign, or to target an upgrade.
- Lookalike audiences: built from your best customers rather than from all your visitors, they remain the most effective acquisition lever; see lookalike audiences.
- Offline conversion measurement: importing signed sales into the advertising platforms lets bidding optimise on real revenue rather than on forms.
- Segmentation: emails and journeys matched to the customer's stage; see audience segmentation.
- Personalisation: content, offers and recommendations based on history, on the site and in your messages.
- Customer lifetime value: calculating LTV by acquisition channel, which is impossible without first-party data.
The collection rules
First-party data is not exempt from the GDPR. Every collection requires a legal basis, clear information about its purposes, a defined retention period, and the ability to access or delete the data. Consent is required for email prospecting to individuals and for advertising use of the data; in B2B, legitimate interest can suffice for a professional contact in connection with their work, with a right to object. Hashed data passed to advertising platforms remains personal data under the regulation. Clean collection beats high volume: a base of 2,000 consented, active contacts produces more than one of 20,000 bought, inert addresses.
Building your base in practice
- Identify your existing collection points: forms, orders, calls, tills, events; many companies already collect without centralising.
- Centralise in a CRM: one record per person, fed by every channel, with the original source preserved.
- Give people a reason to identify themselves: a guide, a tool, an extended guarantee, order tracking, a loyalty benefit; a form offering nothing in return fills no database.
- Collect consent properly: separate boxes per purpose, readable text, proof kept; the mechanism is described in CMP.
- Keep it fresh: a database loses 20 to 30% of its validity a year; reactivation, cleaning out inactives, updating preferences.
- Activate it: an unused database has no value; the lists must feed your campaigns, your exclusions and your sequences every month.
How GreenRed helps
Rather than juggling several tools, GreenRed's overview brings these metrics together in a single dashboard, compares them over time and tells you which actions come first. You can try it free, with no card, from the Pricing.
Frequently asked questions
What is first-party data?
Data collected directly by a company from its visitors, prospects and customers on its own channels: website, app, shop, emails, customer service. It belongs to the company, depends on no browser, and is becoming the central marketing asset as third-party cookies erode.
What is the difference with third-party data?
Third-party data is bought or supplied by advertising platforms, built from tracking users across sites you don't own. Its availability is closing off as third-party cookies are blocked. First-party data comes from your own customer relationship and remains usable.
How do you use your first-party data in advertising?
By importing customer lists as hashed addresses into Google Ads, Meta or LinkedIn — to retarget, to exclude existing customers from acquisition, to build lookalike audiences from your best customers, and to import offline sales so bidding optimises on real revenue.
Is first-party data subject to the GDPR?
Yes. Every collection requires a legal basis, clear information, a retention period, and respect for the rights of access and deletion. Consent is required for prospecting individuals and for advertising use; hashed addresses remain personal data.