
Harness the power of your
first-party data
What is First-id?
Today, you already have more than 50% of your visitors who you can’t identify. Tomorrow, nearly 90% will be invisible!
First-id enables you to identify and recognize all your consented users on all your sites, from all devices and browsers, without being dependant on emails or third-party cookies.

Advertisers
- Unify and enrich my 1st party data
- To identify, qualify and precisely personalize my interactions with users
- No email
Publishers / Media
- Unify and enrich my 1st party data
- To increase the volume and value of my audiences tenfold
- No email or third-party cookies
Agencies
- Optimize targeting and audience planning
- To increase the reach and impact of my media campaigns
- No third-party cookies
Adtech
- Maximize the interoperability of my tools
- For more precise, personalized and efficient service
- In compliance with RGPD

Whether you are a
media, e-retailer or advertiser
First-id helps you meet your challenges:
Data
- Identify
- Reconciling
- Qualify
- Exchange
Activation
- Target (Re-targeting)
- Address (Reach)
- Mastering repetition (capping frequency)
- Measuring performance
How does First-id help you respond to these challenges?
Deterministic
Precise, persistent identifiers based on a combination of strong signals
Powerful
Cross-domain, cross-device, cross-browser compatible
Interoperable
For use in all your marketing and advertising tools
Partner Sovereignty
The partner controls the creation and transfer of its first-party cookie
GDPR Compliance
User consent, opt-out management and anonymous ID
- Read more
+ 250 partner media sites and advertisers
Latest News
Google’s AI Overviews: 6 levers to remain visible and effective thanks to first-party data
On May 20, 2025, Google made a major strategic shift official: its search engine is becoming an answer engine, boosted…
Third-Party Cookies: The Great Comeback (or Not)? Why First-Party Data Remains More Essential Than Ever
Five years of announcements, U-turns, promises, and prototypes... only to end up back at square one. That’s how many in…
Drive-to-Store Measurement: An Unprecedented Mobile Web ROI with Deterministic Identifier
For an automotive campaign, 366 decided to work with Smart Traffik and First-id to measure the effectiveness of drive-to-store advertising…
Rethinking Ad Targeting: Partnership Between First-id and Implcit
First-id and Implcit are joining forces to offer a strong and innovative European alternative in an advertising market undergoing major…