USDD (Decentralized USD) is a decentralized, over‑collateralized stablecoin designed to maintain a 1:1 peg to the U.S. dollar while offering a censorship‑resistant, transparent medium of value for payments, trading, and DeFi (decentralized finance). It was launched in May 2022 by the TRON DAO Reserve as a decentralized alternative to centralized fiat‑backed stablecoins and operates across multiple blockchain networks, including TRON, Ethereum, and BNB Chain.