All terms
A bot buys before your swap and sells after it, taking the difference.
The bot sees your pending swap in the mempool. It buys the token first, pushing the price up, lets your trade execute at that worse price, then sells immediately after.
Your slippage tolerance sets the ceiling on how much they can take. A high tolerance is an open invitation.
Keep slippage as tight as the trade allows, and use protected routing like 1inch Fusion or a private relay for larger swaps.
That it only happens on huge trades. It happens wherever the profit clears the cost, which on a thin pool can be a few hundred dollars. Setting a tight slippage limit is what makes your trade not worth attacking.
Common questions
Why does a high slippage tolerance cost me money?
Do sandwich attacks happen on every chain?
Where this comes up on the site
The guides that actually use this word, rather than a list of everything we have written.
Where to go next
More security terms
Want this explained out loud?
Some of these land faster in conversation than in writing. Sessions are one to one and you can ask anything, including the things that feel too obvious to ask.