Sai (SAI) is a decentralized stablecoin built on the Ethereum blockchain. It was created by the MakerDAO project as a way to maintain a stable value against the US dollar. SAI is collateralized by ether (ETH) and is governed by a decentralized community of stakeholders. Users can mint SAI by locking up ETH in a smart contract, and can redeem it for ETH at any time. Sai is designed to provide stability and predictability in the volatile world of cryptocurrencies.