Donut is an app that plugs into decentralized finance platform DeFi to offer users a handsome 4% return on deposits. Donut invests in high-yield DeFi platforms like Aave and Yearn, but "abstracts away" the DeFi part of it so that users feel they are investing in an ordinary savings product. The software also includes a few features found in other banking apps, such as automated deposits and facility for making tiny contributions by "rounding up" debit card transactions.