Dai is an asset-backed, hard currency for the 21st century. The first decentralized stablecoin on the Ethereum blockchain.
DAI technology is set in such a way that it is backed in excess by collateral at all times, so you never have to worry about its value moving up or down.
Every Dai is backed by another asset of value. DAI collateral portfolio is diversified, allowing multiple assets to guarantee the value of each Dai.