Unified ID 2.0

Leading open-source cookie alternative for the open internet, with broad adoption across DSPs, SSPs, publishers, and data platforms 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, with explicit user consent. The framework is designed to work across the open internet, enabling advertisers, publishers, and data partners to maintain addressability in a post-cookie world while respecting user privacy preferences. UID2 operates as a collaborative industry standard rather than a proprietary product, with adoption spanning major DSPs, SSPs, data platforms, and publishers globally. Participants include major players such as LiveRamp, Publicis, Nielsen, and hundreds of publishers who have integrated the framework into their identity infrastructure. The system includes a transparent opt-out mechanism, allowing users to remove themselves from UID2-based targeting across all participating platforms simultaneously. In the AdTech ecosystem, UID2 is considered one of the most significant and widely adopted cookie alternatives, particularly in the United States. It competes with other identity solutions such as LiveRamp's RampID, Google's Privacy Sandbox, and ID5, but distinguishes itself through its open-source nature, broad industry backing, and interoperability across the programmatic supply chain. Its governance model and scale of adoption make it a foundational piece of the industry's transition away from third-party cookies.