MEV Economics: Builders, Searchers, Validators

What you'll learn

• The Full Value Chain
• Searchers and Builders
• Relays and Validators
• Block Construction Economics and the Trust Problem
• MEV Redistribution and Solana MEV Economics
• The "MEV Is Inevitable" vs "MEV Is a Bug" Debate
• For Deeper Reading

Key terms

Searcher

Actor (typically an individual or small team) running automated bots that identify MEV opportunities (arbitrage, liquidations, sandwiches, etc.) and submit bundles to builders. Typically earn ~30% of gross MEV. Hundreds of independent searchers in the ecosystem.

Builder

Specialized firm that combines searcher bundles into profitable blocks and bids them to validators. Highly consolidated market: Titan Builder ~52%, BuilderNet ~25%, Quasar ~15% as of April 2026.

Relay (MEV-Boost)

Trusted intermediary between builders and validators. Receives sealed blocks from builders, shows headers to validators, enforces commit-before-reveal pattern. Major relays: Flashbots, BuilderNet, Ultrasound, Eden, Manifold.

Trust the Relay Assumption

Architectural weakness of MEV-Boost: validators must trust relays not to leak block contents, front-run commitments, or collude with builders. Mitigated by validators connecting to multiple relays.

Optimistic Relays

Reform to MEV-Boost where the relay commits to validator that block is valid; if wrong, relay is slashed. Reduces but does not eliminate trust requirement.

ePBS (Enshrined Proposer-Builder Separation)

Protocol-level reform to bring MEV-Boost-like functionality into Ethereum consensus directly, eliminating the need for trusted relays. On Ethereum roadmap; in research as of 2026.

Inclusion Lists

Proposed mechanism allowing validators to specify transactions that builders must include in any block. Reduces builder censorship discretion.

Fair Sequencing Services (FSS)

Cryptographic protocols that enforce fair transaction ordering, eliminating MEV at the protocol level. Examples: Espresso Sequencer (used by several L2s), Astria (similar shared sequencer).

CowSwap MEV Blocker (Redistribution)

CoW DAO's public RPC service that routes through builders with anti-sandwich and revenue-sharing agreements. Shares 90% of winning searcher's bid back to the user. Most user-favorable MEV-redistribution model in production.

Validator MEV Income

Additional income validators earn via MEV-Boost on top of standard staking rewards. Typical 0.04-0.10 ETH per proposed block from MEV; aggregate annual uplift of 20-40% on top of base staking returns.

Jito (Solana)

Dominant Solana MEV infrastructure used by ~93% of Solana validators. Jito-Solana validator client routes bundles through tip-based auctions. Cumulative tips paid to validators/stakers: ~$674M through end-2024.

MEV Inevitability vs Bug Thesis

Two opposing views of MEV. Inevitability: MEV is structural to any permissionless market with ordering; the goal is transparency and redistribution. Bug: MEV is a fixable artifact of immature protocol design; cryptographic sequencing and batch auctions can eliminate it.