Maximal Extractable Value — profit that block producers can make by reordering, inserting, or censoring transactions.
Maximal Extractable Value (MEV) is the profit that block producers (miners or validators) and specialized searchers can extract by manipulating the order of transactions within a block. Common MEV strategies include frontrunning (inserting a transaction before a known large trade to profit from the price impact), sandwich attacks (placing transactions before and after a victim's trade), and arbitrage (exploiting price differences between DEXs). MEV is often called an 'invisible tax' on regular users — when you make a large DEX swap, MEV bots may sandwich your trade, worsening your execution price. The annual MEV extracted on Ethereum is estimated in hundreds of millions of dollars. Solutions like Flashbots (private transaction pools), MEV-aware DEXs, and proposer-builder separation aim to minimize harmful MEV while redirecting beneficial MEV (like arbitrage that equalizes prices) back to users or validators.
Maximal Extractable Value is the profit that block producers (miners or validators) can capture by strategically ordering, inserting, or censoring transactions within blocks. Common MEV strategies include: arbitrage (buying on a DEX where the price is lower and selling where it's higher), liquidations (front-running liquidation calls on lending protocols), and sandwich attacks (placing orders before and after a user's trade to profit from the price impact). MEV is controversial because sandwich attacks directly extract value from regular users. The MEV ecosystem has evolved into a sophisticated market: specialized 'searchers' find profitable opportunities, 'builders' construct optimal blocks, and validators choose the most profitable block to propose. On Ethereum, MEV-Boost middleware facilitates this auction process. MEV extraction generates billions annually and has fundamentally changed how blockchain transactions are processed. Solutions like private transaction pools (Flashbots Protect) shield users from sandwich attacks.
In a sandwich attack, an MEV bot sees your pending $50,000 Uniswap swap, places a buy order just before yours (raising the price you pay), then sells immediately after your trade completes — pocketing the price difference.
Yes — sandwich attacks specifically target DEX trades by large retail users. When you submit a swap on Uniswap, MEV bots can detect your pending transaction, buy before you (pushing the price up), let your trade execute at the higher price, then sell immediately after for profit. Use MEV-protection tools like Flashbots Protect or MEV-blocking RPC endpoints to reduce your exposure.