Exactly is a lending protocol built around a date. Every market lends one asset two ways at once: a floating pool, where deposits earn and borrows pay a rate that moves with utilization, and a ladder of fixed-rate pools, one maturing every four weeks, where a borrow's cost and a deposit's return are settled the moment they are made.

The two halves lean on each other. The floating pool backs the fixed pools, lending them what their borrowers take beyond what their depositors supplied, and earns the fees that lending pays. A floating deposit is an ERC-4626 share whose value rises with all of it. One auditor values an account across every market it has entered, each at its price feed and adjust factor, so collateral and debt in any market weigh on the same health.

A fixed rate is a promise about a date, and dates arrive. The debt that was cheap to lock in owes a penalty for every second it sits past maturity. The deposit that was earning a fixed fee stops earning when its pool matures. Repaying early earns a discount that changes with the pool, and the floating rate drifts while all of it sits.

Every number Exactly keeps is a step in a plug: a market's floating assets and borrows, the balance of each fixed-rate pool, an account's position and debt at every maturity, its total debt, and the collateral the auditor sees against it. Depositing, borrowing, repaying and withdrawing, floating or at a maturity, and entering and exiting markets run when a condition is met rather than when someone happens to be watching.

A fixed-rate debt repaid the day before its maturity, not the week after. A matured deposit collected and rolled into the next pool the block it matures. Collateral topped up before the auditor's margin runs out.

Fixed rates only pay off for the accounts that keep their dates, and every date Exactly sets is one a rule can keep.