Unified ID 2.0 (UID2)
Unified ID 2.0 is an open-source, deterministic identity framework seeded by The Trade Desk and now governed by the IAB Tech Lab. UID2 resolves hashed email addresses and phone numbers into rotating tokens that publishers, DSPs, SSPs, and measurement vendors can use for addressable advertising without third-party cookies. The EUID variant provides a GDPR-aligned European deployment.