MEV (Maximal Extractable Value)

Maximal Extractable Value (MEV) — originally "miner extractable value" — is the profit that can be captured by controlling the ordering, inclusion, or exclusion of transactions within a block. Because a block proposer (or a searcher paying for priority) decides transaction order, they can extract value at the expense of ordinary users.

Common MEV Strategies

• Sandwich attacks: buy before a victim's swap, let it fill at a worse price, then sell — the payoff behind insufficient slippage protection.
• Front-running: copy and prioritize a profitable pending transaction (see front-running).
• Back-running / liquidations: place a transaction immediately after a target one.

Reducing MEV Exposure

Users and protocols reduce MEV harm with tight slippage limits and short deadlines, manipulation-resistant pricing (TWAP), commit-reveal schemes, and private orderflow (relays that keep transactions out of the public mempool).

Frequently Asked Questions

Q: Is all MEV an attack?

A: No. Some MEV (like arbitrage that aligns prices across venues) is neutral or beneficial. Harmful MEV — sandwiches and front-running — extracts value directly from users.

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Q: How do I protect users from MEV?

A: Enforce slippage limits and short deadlines, price against TWAP/Chainlink, use commit-reveal where ordering matters, and consider routing sensitive trades through private orderflow.