Sandwich Attack

A DeFi exploit where an attacker brackets a victim's transaction with their own, profiting from the price slippage they create. The attacker frontruns the victim to buy an asset, then backruns them to sell it at a higher price.

Why it matters on AGON

AGON operates on Base, with USDC as the core collateral for all markets. While placing a bet on /markets is a platform-level action, funding your account via a decentralized exchange is an on-chain event. Every transaction broadcast to the network first enters a public waiting area called the mempool.

MEV bots constantly scan the mempool for profitable opportunities. A large swap from ETH to USDC to load up for a World Cup bracket on /world-cup/bracket is a prime target. The bot sees your trade, frontruns it to push the price up, lets your trade execute at a worse price, then backruns it to sell. You get rekt on the swap before you even place a bet.

How to apply

The primary defense is setting a tight slippage tolerance on your DEX. Slippage is the maximum price change you're willing to accept. Setting it to 0.5% or lower caps the potential profit for an attacker. If their sandwich attempt would push the price past your limit, your transaction simply fails instead of executing at a bad rate.

For significant size, use tools that offer private transaction routing. Services like Flashbots or private RPC endpoints send your transaction directly to validators, bypassing the public mempool where predatory bots operate. Splitting a large trade into smaller, randomized chunks also works by making the potential profit too small to be worth the gas.

See also

mev · frontrun · backrun · slashing

Trading prediction markets involves risk. Not financial advice.