USDU is a Bitcoin-backed CDP (Collateralized Debt Position) stablecoin built on Starknet, designed to unlock liquidity for Bitcoin holders in DeFi. The protocol allows users to deposit Bitcoin collateral and mint USDU stablecoins at user-set interest rates, maintaining a 1:1 peg with the US dollar through a redemption mechanism. USDU is part of Uncap, a dual-protocol system that serves as the liquidity engine for Bitcoin finance (BTCFi). The stablecoin features a permissionless liquidation system managed through a stability pool, where 75% of borrowing interest is distributed to stability pool participants and 25% is allocated as Protocol Incentivized Liquidity (PIL) to USDU-denominated trading pools on Ekubo DEX. The protocol is based on Liquity v2 architecture, adapted for Bitcoin collateral on Starknet. USDU aims to serve as a foundational asset for the BTCFi ecosystem, providing censorship-resistant, trust-minimized stablecoin infrastructure that enables sustainable yield opportunities for Bitcoin holders without requiring them to sell their BTC holdings.