Saffron is a new fixed yield DeFi primitive. Saffron vaults split fees earned on Uniswap into fixed and variable yield. Fixed yield is paid upfront. Variable yield buyers earn all future yield from the deposited Uniswap position. Saffron vaults are permissionless, immutable, and non-upgradable smart contracts live on all EVM chains. Uniswap fees are the first underlying yield source for Saffron vaults.