A stablecoin is a crypto token designed to hold its value stable against a reference asset — usually the US dollar. Stablecoins let users hold a "digital dollar" on-chain without leaving the crypto ecosystem for fiat banking rails.
Three main designs: - **Fiat-backed**: the issuer holds a 1:1 reserve of dollars (or cash-equivalents) for every token in circulation. USDC (Circle), USDT (Tether), PYUSD (PayPal) are the dominant examples. - **Crypto-collateralized**: users lock crypto at an overcollateralized ratio (typically 130-200%) to mint stablecoins. DAI/USDS (Sky) is the canonical version. - **Algorithmic**: supply expands and contracts via a mint-and-burn relationship with a secondary token. Every algorithmic stablecoin that reached meaningful scale has collapsed. TerraUSD's May 2022 implosion is the canonical warning.
Stablecoins are the most-used crypto product by transaction volume. They dominate DeFi liquidity pools, serve as the settlement rail for cross-border remittances, and represent the majority of on-ramp conversion volume.
Regulatory posture varies: USDC holds licenses in the US, EU (MiCA EMT), and Japan. USDT does not meet MiCA standards in the EU. For serious balances, reserve transparency and regulatory clarity matter more than marketing.