How Do Private Transaction Relays Prevent the Visibility Required for Front-Running?

Private transaction relays, like those offered by Flashbots, allow a trader to submit a transaction directly to a block builder or validator. This bypasses the public mempool entirely, meaning the pending transaction is not visible to general-purpose front-running bots.

The transaction is included in a block only when it is confirmed, eliminating the opportunity for an attacker to see it and place a preemptive order. This process effectively creates a 'dark pool' for the specific transaction.