A stablecoin is a token engineered to hold the price of a reference asset, almost always a fiat currency: one USDC aims to be worth one dollar today, tomorrow, and at settlement. Issuers back that promise with reserves (bank deposits, T-bills, or the reference currency itself) and publish attestations so holders can check.
Because the price stands still while the settlement stays on-chain, stablecoins do the job cash does in a portfolio and a ledger does in a payment system. Merchants price in them without FX drama; treasurers hold them between settlements; rails clear them with crypto finality.
A stablecoin holds its price by being redeemable for the thing it tracks. Issuer-backed models keep a reserve of dollars, bonds, or metal and let authorized participants mint a token by depositing the asset and burn it to withdraw. When the token's market price drifts, arbitrageurs close the gap: buy the cheap token and redeem it, or mint and sell the expensive one. That loop, not promises, is what pins the peg.
Decentralized models skip the issuer by holding collateral on-chain in a contract and minting tokens against it, with over-collateralization absorbing price swings. Both models settle identically once issued: the token is a standard asset on its chain, transferable by any wallet that holds it.
The operational detail that matters at checkout is confirmation behavior. A stablecoin transfer is final when its chain finalizes: seconds on an L2 or Solana, longer on Ethereum mainnet at congestion. Pricing at checkout quotes live, so the amount the buyer signs for is the amount that arrives, with no settlement window in which the value can drift materially.
A merchant in Lagos prices invoices in naira but gets paid in cNGN, a naira-pegged token. The customer pays from any wallet, the token arrives in minutes, and the merchant either holds it or exits through a local rail. The same shape runs in reais with BRZ-style tokens and in dollars with USDT or USDC, where the reserve is a audited dollar pool.
Twenty-four stablecoins trade on U.CASH across the dollar, euro, yen, and fourteen other currencies, each with its issuer, peg, and reserve posture on its own page. Checkouts price them from fiat FX tables or their own market feed, never from a thin pool.
For a merchant, the peg is the product: a USD token receipt behaves like a dollar receipt, a EUR token like euros. Checkout can offer the stablecoin families that match the invoicing currency and let buyers pick the token, which removes the volatility objection without adding a conversion step.
Every term behind the rails, the assets, and the settlement.