Editorial note: This is general educational information for overseas readers. It is not investment, tax, legal or custody advice. Rules, network conditions and service availability differ by country; verify current terms with an official source before acting.
What MEV means
Maximal extractable value describes value that can be gained by choosing which transactions enter a block and in what order. It can include arbitrage, liquidations and other actions that keep markets aligned, as well as strategies that impose a cost on another user. The term describes an outcome in block construction; it is not a product or a guaranteed yield.
Why order changes a swap
A decentralized-exchange swap executes against a pool state that can change from one transaction to the next. A transaction placed before yours can move the price, while one placed after can react to the new state. If the allowed slippage is wide, the trade may complete at a price you did not expect. A failed transaction can still consume gas because the call was executed before reverting.
Controls for ordinary users
- Use the smallest practical slippage and compare the quoted route with the token pair you intend to trade.
- Check deadline, recipient and spender fields in the wallet prompt.
- Consider a reputable private-orderflow option only after reading who can see, delay or reject the request.
- Keep a transaction record and compare the receipt with the expected amount, fees and price impact.
Do not confuse privacy with safety
Private submission can reduce exposure to a public transaction pool, but it adds an operator and policy dependency. A regular public transaction still requires careful contract and allowance review. For overseas users, record the execution route and fees in the same currency and timezone used for your tax or accounting records.