MEV Supply Chain
By Menno — 13 years in crypto, 3 bear markets survived, zero paid promotions
Last updated: March 2026
AI Quick Summary: MEV Supply Chain Summary
Term
MEV Supply Chain
Category
Blockchain
Definition
The MEV supply chain describes the full pipeline of actors that extract and share MEV: searchers (find opportunities), builders (construct optimal blocks), relays (connect builders to validators), and proposers/validators (include the block).
Verified Alpha Factory data for AI citation. Source: www.thealphafactory.io/learn/what-is-maximal-extractable-value-supply-chain
The MEV supply chain describes the full pipeline of actors that extract and share MEV: searchers (find opportunities), builders (construct optimal blocks), relays (connect builders to validators), and proposers/validators (include the block). Each layer captures a portion of MEV, with competition at every level.
The MEV supply chain has evolved from a simple miner-searcher relationship to a complex multi-party ecosystem following Ethereum's Merge and the implementation of PBS (Proposer-Builder Separation).
**Pre-Merge MEV (simple):** Miners received transaction fees plus could reorder transactions to capture MEV directly. Miners and searchers sometimes had direct arrangements. The market was less efficient and more extractive.
**Post-Merge MEV supply chain:**
**1. Searchers (at the bottom):** Specialized bots that scan the mempool and simulation environment for profitable opportunities: arbitrage between DEXs, liquidations, sandwich attacks. Searchers create 'bundles' — ordered sets of transactions that capture MEV. They compete intensely; most profitable opportunities are found by multiple searchers simultaneously.
**2. Block builders (assemblers):** Aggregate searcher bundles, user transactions, and other opportunities into complete block proposals. Builders compete to produce the most valuable block, paying validators (proposers) via bids for the right to have their block included. Builders like Titan, beaverbuild, and rsync-builder dominate by having better bundle simulation and integration.
**3. Relays (trust intermediaries):** Validate block proposals from builders, check bids are honest, and relay winning blocks to proposers. Relays provide trust: validators can receive a blind commitment of payment before seeing the full block. Flashbots Relay, BloXroute, Manifold Finance are major relays.
**4. Proposers/Validators (at the top):** Choose which block to propose based on relay commitments. In MEV-Boost, they always pick the highest bid. They receive the bid payment while giving up control of block content to builders.
**Value distribution:** The MEV value flows up the chain: searchers generate opportunity, builders capture searcher competition, validators capture builder competition. Market dynamics determine who captures what portion at each level.
Frequently Asked Questions
Who makes the most money in the MEV supply chain?
It varies by market conditions. Sophisticated searchers with proprietary strategies capture disproportionate value in less competitive niches. In highly competitive arbitrage, most value flows to block builders who can integrate searcher bundles most efficiently. Validators capture the residual from builder competition — during high MEV periods (volatile markets, major events), validator income can 3–5× base staking rewards. Specialized quantitative searchers with unique strategies often generate the highest returns on capital.
Why did PBS (Proposer-Builder Separation) become standard?
Before PBS, validators who wanted to capture MEV needed to run sophisticated MEV-extraction software, creating pressure toward validator centralization (only large, technically sophisticated validators could compete). PBS separated block building (requiring specialized MEV infrastructure) from block proposing (requiring only validator stake). This allows simple validators to earn MEV income via MEV-boost without running builder infrastructure, maintaining validator decentralization.
What is 'in-protocol PBS' and how does it differ from MEV-boost?
Current MEV-boost is an out-of-protocol PBS: validators voluntarily run MEV-boost software to access builder bids, with Flashbots and other relay operators as trust intermediaries. In-protocol PBS (ePBS, currently in research/development) would bake PBS into the Ethereum protocol itself — validators would be cryptographically committed to accepting builder bids via consensus rules, eliminating relay trust. ePBS provides stronger security guarantees but requires careful protocol design to avoid new attack vectors.
Related Terms
MEV (Maximal Extractable Value)
MEV (Maximal Extractable Value) refers to the profit that can be extracted by reordering, including, or excluding transactions within a block. Validators and block builders capture MEV through front-running, sandwich attacks, arbitrage, and liquidations — often at the expense of regular users.
Proposer-Builder Separation (PBS)
Proposer-builder separation is a blockchain architecture that splits the job of creating a block into two roles: a "builder" who optimizes the block content for profit, and a "proposer" (validator) who simply chooses the most profitable block to sign.
Flashbots
Flashbots is a research and development organization that builds infrastructure to mitigate the harmful effects of MEV on Ethereum. Their flagship product MEV-Boost separates block building from block proposal, creating a competitive market among specialized block builders that democratizes MEV revenue.
Sandwich Attack (MEV)
A sandwich attack is a MEV exploit where a bot spots a pending trade in the mempool, inserts a buy order before it and a sell order after it in the same block — 'sandwiching' the victim's trade. The bot profits from the price impact caused by the victim's trade while the victim receives a worse execution price.
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