MEV-Boost

First, one simple idea to hold in your head

MEV-Boost separates “who builds the block” from “who proposes the block”.

That’s it. Everything else is detail.

Think of it like this 👇

• Builder = expert chef (finds best MEV, arranges transactions)

• Validator (Proposer) = judge (just picks the best dish, doesn’t cook)

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Why is MEV dangerous without MEV-Boost?

Let’s ask WHY first.

Without MEV-Boost:

• Validators:

  • See all transactions

  • Decide order

  • Capture MEV themselves

• Big validators:

  • Invest in better bots

  • Earn more MEV

  • Get bigger

  • Become centralized

• Users:

  • Get frontrun

  • Pay higher gas

  • Get sandwich attacked

So the problem is power concentration.

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What MEV-Boost does (super simple flow)

Step 1: Searchers find MEV

• Searchers = bots/traders

• They find arbitrage, liquidations, etc.

• They do NOT send txs to public mempool

👉 This avoids frontrunning wars.

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Step 2: Builders build blocks

• Builders:

  • Collect bundles from many searchers

  • Arrange txs in the most profitable order

  • Build a full block

• They calculate:

  • “How much ETH can I pay the validator?”

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Step 3: Validators only see a promise, not the block

This is the most important protection.

• Builder sends validator:

  • A block header

  • A number: “I will pay you 2 ETH”

• Validator:

  • Cannot see transactions

  • Cannot steal MEV

  • Just picks the highest paying header

👉 This removes validator greed.

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Step 4: Commit → Reveal

1. Validator signs the header (commit)

2. Builder reveals block body (transactions)

3. Block goes on-chain

4. Validator gets paid

This is called commit–reveal.

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Why this protects Ethereum from BAD MEV

Now let’s directly map problem → solution.

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1️⃣ Stops validator centralization

Problem:

• Big validators earn more MEV

• Small validators can’t compete

• Leads to staking pools dominating

MEV-Boost solution:

• Any validator (even solo staker):

  • Can receive blocks from the same global builders

• Validators don’t need:

  • MEV bots

  • Infrastructure

  • Private deals

👉 Equal opportunity MEV access

This keeps solo staking viable.

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2️⃣ Prevents validators from abusing users

Problem:

• Validator sees your transaction

• Reorders it

• Sandwich attacks you

MEV-Boost solution:

• Validator:

  • Never sees txs

  • Only sees a number (ETH payout)

👉 No knowledge = no manipulation

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3️⃣ Reduces gas wars (PGA)

Problem:

• Bots spam higher gas

• Network congested

• Normal users pay more

MEV-Boost solution:

• Bots:

  • Send one sealed bid

  • Off-chain

• No mempool bidding war

👉 Lower gas for everyone.

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4️⃣ Improves user privacy

Problem:

• Public mempool = “Dark Forest”

• Everyone can see your tx and attack it

MEV-Boost solution:

• Searcher txs:

  • Skip public mempool

  • Go privately to builders

👉 Less frontrunning, less sandwiching.

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5️⃣ Reduces consensus attacks (reorgs)

Problem:

• Validator sees profitable block

• Reorgs chain to steal MEV

• Hurts finality and trust

MEV-Boost solution:

• Validator signs before seeing block

• Cannot decide to reorg based on contents

👉 No incentive to reorg

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How MEV-Boost protects the PROTOCOL itself

Risk	How MEV-Boost helps
Validator collusion	Validators can’t negotiate privately
Chain reorgs	No block visibility before signing
Centralization	Equal MEV access
Off-chain bribery	Transparent bidding via relays
Mempool chaos	Auctions moved off-chain

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Relays & Escrows (very simple)

• Relay:

  • Gatekeeper

  • Checks block validity

  • Protects validator from bad blocks

• Escrow:

  • Ensures data is available

  • Prevents cheating during reveal

Think of them as referees, not players.

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How this leads to Proposer-Builder Separation (PBS)

MEV-Boost is:

• ❌ Not in protocol

• ✅ A working prototype

Future Ethereum plan:

• PBS inside consensus

• No external relays

• Even stronger decentralization

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One-line mental model (remember this)

MEV-Boost takes MEV power away from validators and gives it to a competitive market of builders, while protecting users and keeping Ethereum decentralized.