MEV

MEV, or maximal extractable value, is the value that can be extracted by deciding which transactions go into a block and in what order. Specialised bots called searchers, along with whoever builds the blocks, do this. Some MEV is neutral, such as arbitrage that aligns prices across exchanges or loan liquidations.

For a memecoin trader the important kind is the harmful one: bots see your pending swap and place their own transactions right before and right after it, profiting from the price difference. Large swaps in shallow pools with high slippage are the most exposed. On Solana and on EVM networks there are services that send transactions with MEV protection, which reduce this risk.