What Is a Sandwich Attack? Meaning in Crypto
Sandwich attack: A sandwich attack is an MEV trade where a bot buys just before your swap and sells just after it, so you get a worse price and the bot keeps the difference.
Key takeaways
- A sandwich attack places a bot's buy before your swap and its sell after it; your trade sits in the middle, like the filling of a sandwich.
- You pay a higher price on your buy, up to your slippage tolerance, and the bot keeps the difference.
- Large swaps in small memecoin pools with a high slippage tolerance are the easiest targets.
A sandwich attack is an MEV trade where a bot buys a token just before your swap and sells it just after. Your swap pushes the price up between the two bot trades, so you pay more and the bot keeps the difference. Memecoin buys with a high slippage tolerance are common targets.
How a sandwich attack works
Ethereum.org describes the method: a searcher "will watch the mempool for large DEX trades", buys before the large trade, and sells after it at the higher price (Ethereum.org). The same idea applies on Solana, where bots compete for the position next to large swaps.
Example: you buy 5 SOL of a memecoin with a 20% slippage tolerance in a small pool.
- A bot buys first and pushes the price up close to your limit.
- Your buy fills at that higher price.
- The bot sells into the price that your buy created.
You end up with fewer tokens, and the bot takes the gap as profit.
Why it matters for traders
The tolerance you set is the maximum a bot can take from you. Keep it low, split large orders, and prefer routes with MEV protection: Jito, for example, offers sandwich mitigation for Solana transactions (Jito docs). Read more on MEV and compare trading tools in our memecoin trading platforms hub.