What Is a Mempool and Why Is Its Transparency a Key Enabler of MEV?

The mempool, or memory pool, is a waiting area for unconfirmed transactions before they are selected and included in a block by a validator or miner. It functions as a public queue of pending operations.

Its transparency is the primary enabler of MEV because it allows malicious actors to monitor the stream of transactions, identify profitable opportunities like large trades, and then construct their own transactions to front-run or sandwich the original order. Without this public visibility, MEV extraction would be significantly harder.