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Brief
ID5

ID5

Identity Resolutionid5.io

ID5 is an adaptive identity technology company that connects fragmented signals across environments to make digital advertising addressable and measurable across channels.

Last updated Oct 5, 2026 by the ATDb Editorial Team

Founded
2017
HQ
London, United Kingdom
Connections
34

AI-drafted from public sources8 sources cited

At a glance

Employees
51-200
Funding
~$20M
Revenue
$5M-$20M
Stock
N/A
19integrations10competitors

About

Leading independent, neutral identity infrastructure provider for the open web, widely adopted across publishers, SSPs, DSPs, and data platforms globally.

ID5 is an adaptive identity technology company that connects fragmented signals across environments to make digital advertising addressable and measurable across channels. Its omnichannel identity infrastructure is designed to serve the entire ecosystem, fostering collaboration among advertisers, publishers, and technology partners. Its flagship product, the ID5 ID, is a universal identifier that enables publishers, advertisers, and ad tech platforms to recognize users and deliver targeted, measurable campaigns across devices without relying on third-party cookies or mobile advertising IDs. ID5 also offers a cross-device graph that allows marketers to deploy people-based marketing strategies by connecting different signals to the same individual or household across devices. The ID5 ID is built with data protection in mind, leveraging consent signals and an encryption mechanism to ensure that users' privacy preferences are respected and enforced across the advertising value chain. There are no stated minimum traffic requirements to work with ID5, and integration is free. Source 1: id5.io — Holding Identity to Higher Standards - ID5.io Source 2: id5.io — Adaptive Identity for Omnichannel Advertising - ID5 Source 3: iabuk.com — ID5 ID and Cross-Device Graph Source 4: playwire.com — Ad Tech Ecosystem: ID5

Business model

SaaS / API-based platform

Target market

Enterprise

What they offer

  • ID5 Universal ID

    A shared, privacy-compliant persistent identifier that replaces third-party cookies for audience targeting, frequency capping, and measurement across the open web.

  • ID5 Private ID Cloud

    A private, first-party identity solution that allows publishers and platforms to create and manage their own identity infrastructure using ID5 technology.

  • ID5 Identity API

    An API that enables publishers and ad tech platforms to retrieve and integrate the ID5 Universal ID into their existing tech stacks.

  • Consent Management Integration

    Built-in support for IAB TCF and other consent frameworks to ensure privacy compliance when generating and sharing identity signals.

Key features

Privacy-compliant universal identifier (ID5 ID)Support for authenticated and unauthenticated environmentsFirst-party data integration and signal enrichmentIAB TCF and GDPR/CCPA complianceInteroperability across DSPs, SSPs, DMPs, and data platformsDeterministic and probabilistic matchingReal-time identity resolution via APINeutral, non-competitive infrastructure model

Use cases

Cookieless audience targeting for programmatic advertisingCross-site frequency capping without third-party cookiesAttribution and measurement in privacy-compliant environmentsPublisher monetization in a post-cookie worldFirst-party data activation and enrichmentIdentity resolution for DMPs and CDPsSupply-side identity signaling for SSPs

Customer segments

Publishers and media ownersDemand-side platforms (DSPs)Supply-side platforms (SSPs)Data management platforms (DMPs)Customer data platforms (CDPs)Ad networksData providers and data brokersAdvertisers and agencies

Tech & specs

Technology stack

JavaScript tag / client-side SDKRESTful APIServer-to-server integrationPrebid.js integrationIAB TCF 2.0 compliance layerProbabilistic and deterministic identity matchingCloud-based infrastructure

Security & compliance

GDPRCCPAIAB TCF 2.0IAB Europe registered CMPPrivacy by design principles

Deployment

CloudAPI integrationJavaScript tagServer-to-server

API

Yes

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