Decoding the Sandwich Attack: How MEV Bots Exploit Your On-Chain Trades

A sandwich attack is a sophisticated form of Maximal Extractable Value (MEV) exploitation. A predatory bot identifies your pending swap, wraps your transaction between its own buy and sell orders, and siphons off profit from the artificial price volatility it creates. While common on Ethereum, this phenomenon is rampant across all AMM-based ecosystems, including Solana, BSC, Base, and Monad. For most retail traders, these attacks are the primary cause of "invisible losses" — slippage that feels like market volatility but is actually a calculated extraction. The Illusion of Chronological Processing To grasp how a sandwich attack is even possible, we must debunk the myth that blockchains process transactions in the exact order they are received. Blockchains operate in batches called blocks. Instead of executing your swap the microsecond you click the button, the network collects all incoming requests within a specific time window. The order of execution within that block is determined by