What is MEV? How transaction order can cost crypto traders
By SendPay Business · · 2 min read
MEV, short for maximal extractable value, is the extra profit someone can make by choosing which transactions go into a block and in what order. It is most talked about on Ethereum and other networks with busy decentralised exchanges.
How it happens
Pending transactions usually sit in a public waiting area before they are added to a block. Specialised bots watch this area for trades they can profit from, then pay to have their own transactions placed just before or after them.
A sandwich attack
- A bot spots a large pending swap on a decentralised exchange.
- It buys the same token first, pushing the price up.
- The user's swap goes through at the worse price.
- The bot sells straight after, keeping the difference.
Limiting the cost
Setting a tight slippage limit caps how much worse a trade can get. Some wallets and services offer private transaction routes that keep trades out of the public waiting area. Splitting very large trades can also help.
Where SendPay fits
SendPay platforms let customers buy, sell and hold crypto, held with regulated partners, alongside GBP, EUR and USD accounts, powered by licensed partners. SendPay doesn't offer trading tools, DeFi or lending.
Build it
Create your own financial platform.
Pick a template, name it, brand it, preview every page before you pay. Your brand, your users, your fees.
Build my platform →Questions people ask
What did slippage cost me?
Work out slippage and the worst price your tolerance allows.
Slippage calculator →What is the Bitcoin mempool?
The waiting area for transactions before they are added to a block.
Mempool →Read next
This guide is general information, not legal or financial advice. SendPay Business is a technology company, not a bank, and does not take deposits; regulated services on the platforms are provided by licensed partners. PayPal, Patreon and Substack are named as reference points only and are not affiliated with SendPay Business.