1. What is MEV?
On blockchain, whoever packages first has the advantage. Validators can:
- 1.Front-running to push your own trade ahead of others' (front-running)
- 2.Stuffing your own trade behind someone else's (tailing Back-running)
- 3.Sandwich your own trade between two target trades
These are all sources of MEV.
2. The three most common MEV attacks
Sandwich Attack: Your large purchase goes into the mempool waiting to be packed. MEV bots rush to buy and push prices up, allowing you to trade at a higher price, then immediately sell for profit. Your slippage loss is the bot's profit.
- 1.Front-running arbitrage: Your trade reveals arbitrage opportunities (such as spreads between different DEXs), and the bot directly copies your strategy to execute first.
- 2.Liquidation Front-Running: DeFi liquidation opportunities are being watched by multiple people, and bots use gas wars to compete for liquidation rewards.
Sandwich attacks are the deadliest for users. If slippage protection isn't tight enough, you might think it's market price exchange, but in reality, it's the MEV bot collecting taxes.
3. Protection measures: protocol layer
What the DEX protocol layer can do:
- 1.Batch auctions: CoW Swap and others use batch matching, where all orders in the same block share the average price, eliminating the advantage of sorting
- 2.Private Mempool: Flashbots and similar platforms allow transactions to bypass public mempools and go directly to validators
- 3.Commitment-Disclosure Mechanism: Users submit commitments first, and the specific order is only disclosed in the next block, making front-running impossible
- 4.Slippage Protection: Contracts are forced to have a minimum transaction price; if it exceeds slippage, it will roll back
4. Protective measures: User layer
What ordinary users can do:
- 1.Use DEXs that support MEV protection (CoW Swap, 1inch Fusion, etc.)
- 2.Set tight slippage tolerance (small amounts can be 0.1%, large amounts adjusted according to liquidity)
- 3.Large orders can be split or use the TWAP strategy
- 4.Avoid gas peaks, when bots are most active then
5. Can MEV be eradicated?
Honestly: no. As long as miners/validators have the right to order packaging, there is room for arbitrage. But it can greatly alleviate losses, reducing the losses for most users to negligible levels.
For DEX project teams, MEV protection is not just a technical detail, but a key differentiator for user experience and retention.
