Block Height Expiry

Definition ∞ Block height expiry refers to a condition where a transaction or smart contract function becomes invalid after a specific blockchain block number is reached. This mechanism provides a deterministic time limit for operations, relying on the immutable progression of blocks. It helps prevent transactions from remaining pending indefinitely or being executed under outdated market conditions. This feature is common in time-sensitive operations within decentralized finance.
Context ∞ News reports often reference block height expiry when discussing transaction malleability, conditional payments, or oracle updates in decentralized applications. Its application ensures that agreements or trades are finalized within expected timeframes, reducing certain counterparty risks. The reliability of block production rates influences the practical utility of this expiry method.