USDaf is a CDP stablecoin built on Liquity v2 infrastructure by Asymmetry Finance, allowing users to borrow against their BTC and Yield-Bearing Stablecoins with user-set fixed interest rates for the first time. USDaf is immutable by design to ensure the utmost security for a decentralized stablecoin. With USDaf, users can collateralize wBTC, tBTC, ysyBOLD, scrvUSD, sUSDS, and sfrxUSD permissionlessly.