Searchers and Block Builders

Modern MEV is a supply chain. Searchers find opportunities; builders assemble blocks; relays deliver blocks to validators; validators propose the highest-paying block. Each layer takes a cut.

Searchers run sophisticated bots that simulate transactions against pending state. They identify arbitrage, liquidations, and sandwich opportunities, then attach payment to bundles so builders prioritize inclusion.

Competition among builders improves validator payments but concentrates block construction in specialized firms. Relay diversity matters — a small set of relays handling most flow creates censorship and trust risks.