Front Running

Front running is the practice of placing a transaction ahead of a known pending transaction to profit from the expected price movement. In crypto, front running is a form of Maximal Extractable Value (MEV) where bots monitor the mempool for large pending trades, then submit their own transaction with a higher gas fee to get processed first. A common variant is the "sandwich attack," where the attacker places a buy before and a sell after a victim's trade, profiting from the price impact.