UEI and SAM.gov registration, explained

A Unique Entity ID (UEI) is the identifier the US federal government uses for every entity doing federal business — grants, contracts, SBIR/STTR awards included. It replaced the Dun & Bradstreet DUNS number, which had been the standard identifier since 1978; the transition to UEI began in 2019 and completed by April 2022. Unlike DUNS, a UEI is generated directly inside SAM.gov rather than obtained from a third party — there is no separate application to Dun & Bradstreet any more.

SAM.gov (System for Award Management) is where the UEI is assigned and viewable, and where an entity registers and manages the credentials that let it actually receive a federal award. Registering in SAM.gov is a prerequisite for essentially every US federal grant and contract, including every SBIR/STTR award — an eligible small business cannot be paid without it. Existing registered entities were assigned a UEI automatically during the transition, with no re-entry of their existing data required.