First-party data: definition and collection strategy
Updated on February 22, 2026
Quick definition
First-party data is all the data collected directly by an organisation from its own users, customers and prospects via its proprietary channels — website, mobile app, email, loyalty program — with their explicit consent and within a direct relationship. First-party data is the most reliable, accurate and durable type of data in the context of stricter GDPR enforcement and the disappearance of third-party cookies.
How it works
First-party data covers three main families.
Behavioural data: user actions on the site (pages visited, clicks, scroll, time spent, conversions), collected via an analytics tool.
Declared data: information provided by the user themselves during sign-up, purchase or form submission (name, email, preferences).
Transactional data: purchase history, subscriptions, baskets, customer value.
By contrast:
- Second-party data is another player's first-party data shared as part of a partnership
- Third-party data is purchased from brokers without a direct relationship with the user
In a post-cookie context, first-party data is the only truly reliable and sustainable type of data. Internet giants such as Google, Apple and Meta built their empires on first-party data from their own services, giving them a considerable advantage over advertisers who depended on third-party cookies.
The quality of first-party data depends on the richness of the relationship with the user.
Why it matters
First-party data has become the most valuable strategic resource in digital marketing.
- More accurate than third-party data: it comes directly from the source
- More reliable: it is not altered by intermediaries
- More GDPR-compliant: it relies on a consensual relationship
- More durable: it does not depend on third-party cookies
In a context where walled gardens (Google, Meta) reduce data transparency, owning a rich first-party data base is a major competitive advantage.
How to improve or use it
- 1Identify all touchpoints where you can collect data with user consent: sign-ups, quizzes, loyalty programs.
- 2Create premium content (guides, webinars, tools) that prompts anonymous visitors to identify themselves.
- 3Invest in a first-party or cookieless analytics tool to capture browsing behaviour.
- 4Centralise this data in a CDP to activate it in your marketing campaigns.
- 5Deploy a zero-party data strategy to enrich profiles with declared preferences.
With Sublim
Sublim collects exclusively first-party behavioural data from your site, with no dependency on third-party cookies and no transfer to third-party platforms. This GDPR-compliant collection belongs entirely to you and can be exported via the Sublim API to feed your CDP, your marketing automation tools or your predictive models.
Frequently asked questions
Does first-party data require GDPR consent?
It depends on the data type and the purpose. Behavioural data collected via a cookieless analytics tool for aggregated audience measurement may be exempt from consent. Declared data (email, preferences) collected via a form requires a valid legal basis (consent or legitimate interest depending on context).
How can I activate my first-party data without sharing it?
Clean rooms (secure data collaboration spaces) make it possible to match first-party data with a partner's data without sharing the raw data. Tools such as Google Ads Data Hub, AWS Clean Rooms or LiveRamp let you enrich your analyses or ad audiences while preserving data confidentiality.
What is the difference between first-party data and zero-party data?
First-party data is collected observationally by the company via the user's behaviour (pages visited, clicks, purchases). Zero-party data is shared intentionally and proactively by the user themselves (quiz answers, declared preferences, interests). Zero-party data is considered the most accurate and the most consensual.
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