Unified ID 2.0

One of the most widely adopted open-source cookie-replacement identity frameworks in programmatic advertising, with broad DSP, SSP, publisher, and data partner adoption globally.

Unified ID 2.0 (UID2) is an open-source identity solution originally developed by The Trade Desk and subsequently transitioned to independent governance under the Prebid organization and the Partnership for Responsible Addressable Media (PRAM). It replaces third-party cookies with a standardized, interoperable identifier derived from hashed and encrypted user email addresses or phone numbers, enabling advertisers, publishers, and data partners to maintain addressable advertising in a post-cookie world. Users are given transparency and control over their data through opt-out mechanisms managed via a central operator infrastructure. UID2 operates through a network of Operators — both open (community-run) and closed (private) — that manage the encryption and tokenization of user identifiers. Major technology companies including LiveRamp, Criteo, Nielsen, and numerous DSPs, SSPs, and CDPs have integrated UID2 into their platforms, making it one of the most widely adopted cookie-replacement frameworks in the industry. The Trade Desk continues to be a primary contributor and advocate, but the open governance model is designed to prevent single-company control. In the AdTech ecosystem, UID2 is positioned as a leading industry standard for identity resolution in a privacy-first environment, competing with solutions like Google's Privacy Sandbox, LiveRamp's RampID, and ID5. Its significance lies in its open-source nature, broad publisher and advertiser adoption, and its ability to function across the open web, CTV, and mobile environments, making it a critical infrastructure layer for the future of programmatic advertising.