Glossary
Searcher
A bot operator who scans pending transactions and on-chain state for profitable opportunities (arbitrage, liquidations, sandwiching) and bids to capture them.
Searchers are the demand side of the MEV market. They watch the public mempool and on-chain state for opportunities — a DEX imbalance, a borrow position about to be liquidatable, a large pending trade — and submit transactions (or bundles) to capture the value.
Searchers compete on speed, on the quality of their algorithms, and on their access to builders and private order flow. In a healthy PBS market the searcher's profit is squeezed by competition, with most of the value flowing through to the proposer (and ultimately the protocol).