Flash loans allow you to borrow instantly from a publicly funded smart contract pool without providing any collateral. These loans are only valid within one block transaction and must be repaid before the end of the transaction used to borrow the loan. If the borrower does not repay their debt by this time, the transaction is reverted. This process ensures that liquidity is always returned to the pool. Flash loans are commonly used for arbitrage, collateral swapping, self-liquidation, and more.