Decentralized finance (DeFi) as a distinct technological and financial movement began taking shape following the launch of Ethereum in 2015, which introduced programmable smart contracts capable of executing complex financial logic without intermediaries. The ecosystem experienced its foundational breakthrough around 2017 with the creation of early decentralized stablecoins and lending platforms, before capturing mainstream financial attention during the rapid market expansion of the "DeFi Summer" in 2020. Since then, it has evolved into a multi-billion-dollar parallel financial sector.