Morpho Midnight is fixed rate lending on Morpho: a borrower owes a set amount at a set date, and a lender knows on day one exactly what the loan pays at maturity.

Each market is a loan asset, one or more collaterals with their own oracles and liquidation thresholds, and a maturity, fixed when the market is created and never changed afterward. Lending and borrowing happen by trading credit and debt: a lender buys units of credit, each worth one unit of the loan asset at maturity, below par, and the discount is the interest; a borrower sells them against collateral. Makers post offers across many markets at once without locking capital, and takers fill them, so the rate is whatever the two sides agree on rather than what a utilization curve says.

Fixed terms cut both ways. A borrower's debt does not grow, but it is due: once the market matures, any position still owing can be liquidated, healthy or not, with the liquidator's incentive climbing to its full size within the hour. A lender's credit pays out only as borrowers repay or are liquidated, so at maturity what a market holds withdrawable can lag what its lenders are owed, and a loss a liquidation cannot cover is spread across every lender in the market.

Every number that decides a position is a step in a plug: the debt, the credit as it stands after fees and losses, each collateral balance, whether the position is healthy, and how much the market holds withdrawable. Repayment, collateral moves, and withdrawals of credit run when a condition is met rather than when a person is awake.

Debt repaid before maturity opens liquidation on it. Collateral added the moment the health read turns false. Credit withdrawn as soon as repayments make it withdrawable, and again while the withdrawable amount catches up.

A fixed date is the one thing in lending that is guaranteed to arrive, and a plug is always there when it does.