Mempool Lifecycle

The mempool lifecycle describes the journey of a cryptocurrency transaction from its initial broadcast by a user to its final confirmation on the blockchain. When a user initiates a transaction, it enters the mempool, which acts as a temporary staging area or waiting room for unconfirmed transactions.

Nodes in the network receive this transaction, validate its signature and sufficient balance, and hold it in their local mempool. Miners or validators then select transactions from this pool based primarily on the transaction fees offered, prioritizing those that maximize their revenue.

Once a transaction is selected, it is included in a candidate block, which is then broadcast and verified by the network. Upon reaching consensus, the block is appended to the chain, and the transaction is removed from the mempool as it is now considered confirmed.

If a transaction remains in the mempool too long without being picked up, it may be dropped or replaced if the user issues a new transaction with a higher fee. This process is fundamental to market microstructure as it determines the speed and cost of settlement.