Flashbots and Proposer-Builder Separation

Flashbots emerged to mitigate harmful MEV by creating private transaction channels and formalizing proposer-builder separation (PBS) on Ethereum. Most validator MEV today flows through this infrastructure.

Relays see transaction content and could censor. Multiple relay diversity reduces single-point censorship — an ongoing decentralization concern as OFAC-compliant filtering became common.

Flashbots Protect and similar endpoints let users submit transactions privately, skipping public mempool exposure. Free for users on supported chains; a practical first step against sandwich risk.