What is Tether (USDT)?Tether (USDT) is a stablecoin, a type of cryptocurrency pegged to a fiat currency, in this case, the US dollar. It was launched in 2014 and is one of the most widely used stablecoins in the cryptocurrency market. Tether's main purpose is to provide a more stable alternative to volatile cryptocurrencies like Bitcoin. Tether operates on a system where each USDT coin is backed..