What Is a “Proposer-Builder Separation” (PBS) and Its Impact on MEV?

Proposer-Builder Separation (PBS) is an architectural change, primarily in Proof-of-Stake, that separates the role of Proposer (who chooses the final block) from the Builder (who creates the block content and optimizes MEV). Builders bid for the right to have their block included by a Proposer.

This decentralizes the MEV market, prevents the Proposer from unilaterally extracting MEV, and makes the process more competitive and transparent, theoretically reducing the overall harm to users.