Decentralized finance, or DeFi for short, refers to the financial smart contract, DApps (decentralized application), and financial protocols built on the blockchain. There are 5 categories of decentralized finance (DeFi) - lending and borrowing, dex, derivatives, payments, and assets. Lending and borrowing are the most popular use cases of DeFi. It is an extremely popular way that users can earn cryptos from lending and borrowing DeFi protocols. Most loans made in DeFi are secured loans with more collateral cryptos than borrowed value. The breakthrough of DeFi is that the financial service now can be real transparent and borderless with the help of crypto asset and the blockchain technology. People around the world can enjoy the benefit of it equally. The 5 category products of decentralized finance(DeFi) - decentralized exchanges, synthetic assets, payments, flash loans, and assets that are accessible by every user globally can only exist on blockchains.