What it is
Front-running in cryptocurrency refers to a malicious practice where a trader or bot exploits advance knowledge of a pending transaction to execute their own trade before it. For example, if a miner or bot observes a large buy order for a token in the mempool, they might quickly place their own buy order for the same token with a higher gas fee to ensure their transaction is processed first.
This practice allows the front-runner to profit from the price movement caused by the larger, subsequent transaction. Once the large transaction executes and pushes the price up, the front-runner can immediately sell their tokens for a profit. Front-running is a form of market manipulation that exploits network mechanics and latency, making it a significant concern for fairness and market efficiency, especially on decentralized exchanges.
Why it matters
Front-running can lead to unfair price disadvantages for retail investors, affecting their ability to execute trades at expected prices.
Reviewed under editorial standardsUpdated September 26, 2026Not investment advice