MetaMask USD (mUSD) is MetaMask’s own stablecoin, designed to simplify and make crypto usage more practical. Unlike regular cryptocurrencies, which can fluctuate in value, mUSD is pegged to the U.S. dollar, meaning one mUSD is always worth approximately $1. The stablecoin is built directly into the MetaMask wallet. This means that users can buy, hold, swap, send, and even spend it without relying on outside services.