USDT-TRC20 What Is Tether (USDT)? Tether (USDT) is a stablecoin, a type of cryptocurrency which aims to keep cryptocurrency valuations stable. Tether is a blockchain-based cryptocurrency whose cryptocoins in circulation are backed by an equivalent amount of traditional fiat currencies, like the dollar, the euro, or the Japanese yen, which are held in a designated bank account. Tether tokens, the native tokens of the Tether network, trade under the USDT symbol.