DeFi platforms allow people to lend or borrow funds from others, speculate on price movements on a range of assets using derivatives, trade cryptocurrencies, insure against risks, and earn interest in savings-like accounts. DeFi uses a layered architecture and highly composable building blocks. Some DeFi applications promote high-interest rates but are subject to high risk. By October 2020, over $11 billion (worth in cryptocurrency) was deposited in various decentralized finance protocols, which represented more than a tenfold growth during the course of 2020. As of January 2021, approximately $20.5 billion was invested in DeFi.