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MEV Explained: Flashbots, MEV-Boost, and the 2026 Guide

TL;DR

  • MEV (Maximal Extractable Value) is the profit a block producer can earn by reordering, inserting or censoring transactions — first formalised in Phil Daian and Ari Juels' April 2019 paper "Flash Boys 2.0".
  • Flashbots (founded 2020 by Phil Daian, Stephane Gosselin and Tina Zhen, with Hasu as strategy lead) built MEV-Boost, MEV-Share, MEV-Blocker, and is now building SUAVE — the chain for MEV.
  • Post-Merge Ethereum runs on out-of-protocol PBS via MEV-Boost with 90%+ validator adoption. The market is dominated by builders Beaverbuild (~30%), Titan (~25%), Flashbots, BuilderNet, and relays Flashbots, Ultra Sound, Agnostic, BloXroute and Eden.
  • On Solana Jito Labs, the JTO token and JitoSOL liquid staking turn MEV tips into yield for stakers, with ~80% of stake running jito-solana.
  • Users protect themselves with OFAs (CoW Swap, UniswapX, 1inch Fusion) and private RPCs (MEV-Blocker, Flashbots Protect).

Table of contents

What is MEV? (definition)

MEV (Maximal Extractable Value, originally Miner Extractable Value) is the profit available to a block producer or any actor with influence over transaction ordering by including, reordering, or excluding transactions within a block beyond standard fees and block rewards. The term entered the lexicon in April 2019 when Phil Daian, Ari Juels and the Cornell IC3 group published Flash Boys 2.0, the seminal paper that documented how Ethereum's transparent mempool was being exploited by priority-gas-auction bots running arbitrage between decentralised exchanges. Although the paper focused on Ethereum, the conceptual framework applies to every public blockchain with a deterministic ordering and front-runnable mempool — including Solana, Cosmos chains, and even some L2 sequencers.

In 2026 MEV is a mature, multi-billion-dollar-per-year industry. It has its own Flashbots infrastructure stack on Ethereum, Jito Labs on Solana, dozens of professional searcher firms, several public dashboards (libMEV, mevboost.org, mevboost.pics, Relayscan), and a growing set of consumer-facing protections including MEV-Blocker, Flashbots Protect, CoW Protocol and UniswapX.

Types of MEV

Arbitrage

The simplest and most prosocial form: a searcher spots a price discrepancy between two DEXes (say Uniswap v3 and Curve) and atomically buys low, sells high in the same block. Pure arbitrage tightens prices, reducing slippage for everyone. The risk is the gas auction: in a public mempool, multiple searchers bid up gas to be the one who lands the trade, paying the rest as priority fee.

Sandwich attacks

A predatory pattern: a searcher detects a victim's pending swap, front-runs it with a buy that moves the price against them, lets the victim trade at the worse price, then back-runs with a sell. The most prolific Ethereum sandwicher, "Jared from Subway" (the searcher behind address 0x1f2..., often abbreviated 0xJared), has extracted tens of millions of dollars since 2023 according to on-chain analysis. Sandwich-able trades typically have high slippage tolerance, low liquidity venues, and use the public mempool.

Liquidations

When a collateralised loan on Aave or Compound becomes undercollateralised, anyone can repay the bad debt and seize the collateral plus a liquidation incentive (typically 5-10 percent). The race to be first liquidator is a form of MEV — it's prosocial because it keeps lending markets solvent, but the value still flows to whoever has the fastest infrastructure.

Just-In-Time (JIT) liquidity

A sophisticated form unique to concentrated-liquidity AMMs (Uniswap v3, PancakeSwap v3): a searcher detects a large pending swap, mints concentrated liquidity in the exact tick range that swap will cross, captures the LP fee, and burns the position in the same transaction. The swapper still gets a competitive price; the value comes from existing passive LPs whose share is diluted for one block.

Backrunning and CEX-DEX arbitrage

Pure-information forms: a searcher trades on-chain immediately after a CEX moves, or backruns a known-information transaction (e.g. a DAO vote that releases tokens). Symbolic Capital, Wintermute and Propeller Heads are publicly known professional searchers in this space.

Long-tail and toxic forms

Censorship MEV (excluding a transaction to harm a competitor), reorg MEV (proposing chain reorganisations to recapture an MEV opportunity), and oracle manipulation are systemic risks. Most have been mitigated by post-Merge PBS architecture and proposer commitments, but they remain active research areas — see Flashbots' "MEV and the Limits of Scaling".

How MEV-Boost works (technical mechanics)

MEV-Boost is the post-Merge implementation of out-of-protocol Proposer-Builder Separation (PBS). The flow is:

  1. Searcher finds an MEV opportunity. Builds a "bundle" of one or more transactions (often including their own profit-extraction tx) and submits it privately to one or more builders along with a tip.
  2. Builder continuously assembles candidate blocks by greedily packing the highest-bidding bundles plus normal mempool transactions. Top builders run highly optimised pipelines: Beaverbuild, Titan, rsync, Manifold, BuilderNet (cooperative TEE), BloXroute, Ultra Sound, Lido Builder, Penguin, Quasar, Builder0x69, ETH-Builder and Manta. The builder seals each candidate block, computes its bid, and submits the header to one or more relays.
  3. Relay holds the sealed blocks and exposes a getHeader endpoint to validators. Relays are trusted to: (a) not show the block content to anyone except the validator who signs it; (b) not return blocks that fail validation. Major relays in 2026 are Flashbots Relay, Ultra Sound Relay, Agnostic (Agnostic Gnosis Relay), Aestus, BloXroute Max Profit (bloXroute Max Profit company), BloXroute Regulated (bloXroute Regulated company), BloXroute Ethical, Manifold Relay, Eden Relay, Titan Relay and Wenmerge Relay.
  4. Validator runs MEV-Boost as a sidecar to its consensus client. When it's the validator's turn to propose, MEV-Boost queries each registered relay for the highest header bid and signs whichever pays the most. Only after signing does the relay reveal the full block and broadcast it to the network. The validator earns the bid amount; the searcher pays priority + tip; the builder earns the spread.

This separation is critical: the proposer cannot copy the block content to recapture MEV, because they only ever see the header. Paradigm has argued that the relay role itself should be removed in favour of cryptographic primitives (e.g. zero-knowledge attestations of block validity), which is one branch of the enshrined PBS (ePBS) debate Vitalik Buterin and the Ethereum Foundation have been working on since 2023.

MEV-Share: privacy-preserving order flow

MEV-Share is Flashbots' OFA layer launched in 2023. Users (via wallets or RPC) submit pending transactions privately to MEV-Share, which selectively shares partial information ("there is a swap of WETH→USDC of size X happening in the next block, but no signature") with a permissionless searcher pool. Searchers bid backruns; if they win, the user receives a refund of part of the captured value. Critically, MEV-Share never exposes the full pre-image until the bundle lands, preventing front-running.

MEV-Blocker

MEV-Blocker, launched April 2023, is a free RPC endpoint operated jointly by CoW DAO, Beaverbuild and Agnostic Relay. Users point their wallet at the MEV-Blocker RPC; transactions are submitted privately to a builder pool, refunds are paid back as ETH if a backrun monetises the trade. By 2026 MEV-Blocker handles over 5 percent of Ethereum transaction volume and is the default RPC of multiple major wallets.

SUAVE

SUAVE (Single Unifying Auction for Value Expression) is Flashbots' purpose-built blockchain for MEV. It separates intent expression, confidential auction execution and cross-domain settlement. Devnets Centauri (2023) and Andromeda (2024) demonstrated TEE-based block builders running encrypted memory pools. Mainnet is targeted for late 2026 with cross-chain order flow as the killer feature — see Flashbots' Network Anonymized Mempools and Zero Trust Execution Environments.

History / timeline

Key players (entities + research backlinks)

Researchers and founders

Builders (post-Merge Ethereum)

Beaverbuild (~30%), Titan Builder (~25%), Flashbots (~10-15%), BuilderNet, rsync Builder, Manifold Builder, BloXroute Builder, Ultra Sound Builder, Lido Builder, Penguin Builder, Quasar Builder, Builder0x69, ETH-Builder, Manta Builder.

Relays

Flashbots Relay (Flashbots MEV-Boost Relay company), Ultra Sound (Ultra Sound Relay company), Agnostic, Aestus (Aestus Relay company), BloXroute Max Profit, BloXroute Regulated, BloXroute Ethical, Manifold Relay, Eden Relay, Titan Relay.

Searchers

OFAs and intent-based DEXes

Protections and tooling

Solana MEV: Jito

Jito Labs ships the jito-solana validator client, an out-of-protocol fork of Agave (formerly solana-labs) that adds bundle support: searchers send tipped transaction bundles to the Jito Block Engine, which forwards them to the current leader for inclusion in the next 400 ms slot. Tips are paid in SOL and accrue to the validator. Crucially Jito Foundation introduced JitoSOL liquid staking, which automatically distributes a portion of each validator's MEV tips back to JitoSOL holders — turning MEV into a pure-yield product.

By 2026:

MEV in 2026 — current state, market data

Research and reports

The Flashbots Writings (venue:flashbots) corpus is the canonical research library for MEV. Key reads:

Use cases / examples

Cross-DEX arbitrage

A searcher detects WETH/USDC trading at $3,200 on Uniswap v3 and $3,210 on Curve. They construct a single-block bundle: borrow USDC via Aave flashloan → buy WETH on Uniswap → sell WETH on Curve → repay the flashloan → keep the spread. Hundreds of such trades happen every Ethereum block.

Liquidation bot

Aave and Compound positions can become liquidatable when collateral falls below the maintenance margin. A searcher races to be first to call liquidate, repaying the bad debt and seizing collateral plus a 5-10% incentive. In 2026 most liquidations on Ethereum mainnet flow through MEV-Share or direct builder integrations to avoid public mempool gas wars.

CoW Swap batch auction

A user submits an order on CoW Swap: "sell 10,000 USDC for at least 4 ETH". CoW DAO collects orders for ~30 seconds and runs an off-chain Dutch auction among professional solvers; the winning solver fills all orders simultaneously, internalising any coincidence-of-wants and refunding any captured MEV to the user. Because there is no priority-ordered execution, sandwiches are mathematically impossible.

UniswapX intent

A user signs an intent on UniswapX ("at least 4 ETH for 10,000 USDC"). Fillers compete in a Dutch auction; whoever wins sources liquidity (often from off-chain CEX inventory) and settles on-chain. The entire flow is gas-less for the user — fillers pay gas and recoup it from the auction spread.

Solana Jito bundle

A searcher detects a pending Solana liquidation. They submit a bundle to the Jito Block Engine with a 0.05 SOL tip; the bundle reaches the next leader in <50 ms; the validator executes it; the tip is split between the validator and JitoSOL stakers. Roughly 80% of Solana stake participates.

Risks and criticism

Centralisation of block production. With Beaverbuild and Titan producing more than half of Ethereum blocks, the post-Merge target of "decentralised block building" remains unmet. BuilderNet and rbuilder attempt to invert this by making the dominant builder a credibly neutral cooperative.

Censorship. OFAC-compliant relays and US-domiciled builders may filter sanctioned addresses. The Ethereum community publishes per-block censorship statistics on mevboost.pics and validators can opt into neutral-only relay sets via tools like Vouch. Censorship risk is the strongest argument for ePBS.

Sandwich-attack tax on retail. Even with OFA growth, retail users who paste swaps into a public mempool still pay the sandwich tax. Wallet-default protections (Rabby, MetaMask Smart Tx, Phantom) and education are the long-tail fix.

Regulatory risk. Searchers, builders, and relays operate in a legal grey zone. The Tornado Cash prosecutions and OFAC actions have made several US-based teams reduce US-resident headcount. The EU's MiCA framework does not yet specifically address MEV roles.

TEE trust assumptions. SUAVE and BuilderNet rely on Intel SGX or similar TEEs. Side-channel and supply-chain attacks against TEEs are an active research field — Flashbots' ZTEE work addresses some but not all.

Toxic MEV on L2s and rollups. Pre-confirmations, based-rollup designs, and shared sequencers introduce new MEV surfaces that are still being mapped — see rollup-boost.

How to protect yourself from MEV (step-by-step)

  1. Switch your wallet RPC to a private endpoint. Free options: MEV-Blocker, Flashbots Protect. Paid options: BlockNative, BlockEngine. In MetaMask: Settings → Networks → Ethereum Mainnet → RPC URL.
  2. Use intent-based DEX aggregators for swaps. Best-in-class: CoW Swap, UniswapX, 1inch Fusion, Matcha. These eliminate sandwich attacks structurally.
  3. Set tight slippage. Even on a public mempool, 0.1-0.3% slippage caps losses. Default 1-2% slippage settings are exploitable.
  4. Watch token-launch and meme-coin sniping. New tokens are sniper magnets; never set high slippage on launch transactions. Use Pump.fun's anti-sniper or a private tx.
  5. For Solana use Jito's MEV-Protect RPC (free) or any Phantom/Backpack default — most major Solana wallets ship MEV protection in 2026.
  6. For NFT mints route through a private RPC and consider commit-reveal mints to prevent gas-war front-running.
  7. For large size ($100k+) split across multiple OFAs and consider TWAP via CoW Swap's TWAP product or 1inch's twap orders.
  8. For DeFi positions monitor liquidation health daily. Once liquidatable, you cannot avoid MEV — only minimise it by keeping a healthy buffer.

Comparison table

Component Examples What it does 2026 share
Builder Beaverbuild, Titan, Flashbots, BuilderNet, rsync, Manifold, BloXroute Constructs candidate blocks Beaver 30%, Titan 25%, Flash 12%
Relay Flashbots, Ultra Sound, Agnostic, Aestus, BloXroute, Eden Trusted intermediary Flash 25%, US 22%, BloX 18%
OFA / Protection MEV-Blocker, Flashbots Protect, CoW Swap, UniswapX, 1inch Fusion User-side MEV protection 30%+ of DEX volume
Searcher Jared, Wintermute, Symbolic, Propeller, Beaverbuild Searcher Finds MEV opportunities $2B+ cumulative
Solana Jito Labs, Jito Block Engine, JitoSOL Bundle market + LSD ~80% of stake
L2 rollup-boost, Unichain TEE builder Per-rollup PBS Growing 2025-2026

FAQ

What is MEV in crypto?

MEV stands for Maximal (originally Miner) Extractable Value. It is the profit a block producer or sophisticated actor can earn by including, reordering, or excluding transactions in a block beyond the standard gas fees and block reward. The most common forms are arbitrage between decentralised exchanges, sandwich attacks against retail swaps, liquidations of undercollateralised loans, and just-in-time (JIT) liquidity adds on AMMs. The concept was formalised in the April 2019 paper "Flash Boys 2.0" by Phil Daian, Ari Juels and the Cornell IC3 group. Today MEV is a multi-billion-dollar-per-year industry on Ethereum and Solana with its own builders, relays, searchers and protections.

Who founded Flashbots?

Flashbots was founded in 2020 by Phil Daian, Stephane Gosselin and Tina Zhen, with Hasu joining as strategy lead in 2021. The team grew out of Cornell's IC3 research group whose Flash Boys 2.0 paper had documented the existential threat MEV posed to Ethereum's neutrality. Their first product was MEV-Geth (a forked Ethereum client letting miners accept private bundles) which evolved into MEV-Boost after the September 2022 Merge. The organisation is now a research and infrastructure collective that has published over 50 papers, employs 60+ engineers and operates the largest MEV-Boost relay by share.

What is MEV-Boost and why does Ethereum need it?

MEV-Boost is a sidecar middleware Ethereum validators run alongside their consensus client. It implements an out-of-protocol form of Proposer-Builder Separation: validators outsource block construction to specialised builders via competing relays, then sign whichever block pays them the most. Without MEV-Boost, Ethereum validators would either run their own (centralised, well-resourced) builders or leave money on the table, both of which threaten network neutrality. After the Merge in September 2022 adoption rocketed past 90 percent of validators within twelve months and remains above that level in 2026.

What is the difference between a builder and a relay?

Builders construct candidate blocks by ordering bundles from searchers and pending mempool transactions to maximise total bid (priority fees plus searcher tips). Relays are trusted intermediaries between builders and validators: they receive sealed bids from builders, present the highest-paying header to the proposer, and only reveal the full block content after the proposer signs the header. This data-availability separation prevents the proposer from copying a builder's MEV. In 2026 the largest builders by share are Beaverbuild, Titan, Flashbots and BuilderNet; the largest relays are Flashbots, Ultra Sound, Agnostic, Aestus, BloXroute, and Eden.

What is a sandwich attack?

A sandwich attack is a form of MEV where a searcher detects a victim's pending swap on an AMM, front-runs it with a buy that pushes the price up, lets the victim swap at the worse price, then back-runs with a sell to capture the price impact. The most prolific sandwicher on Ethereum, the searcher behind address 0x1f2... known as "Jared from Subway", is estimated to have extracted tens of millions of dollars since 2023. Sandwich attacks are dramatically reduced when users route through MEV-Blocker, CoW Swap, UniswapX, 1inch Fusion or any intent-based DEX that prevents priority-ordered execution.

What is the difference between MEV on Ethereum and MEV on Solana?

On Ethereum, MEV is captured during a 12-second block-building auction: searchers send bundles to builders, builders bid for proposer attention via MEV-Boost relays. On Solana, blocks are produced every 400 ms by a leader scheduled in advance — there is no relay-based auction. Instead Jito Labs developed an out-of-protocol modification (jito-solana validator client) that lets searchers send bundles with tips to the leader, with the Jito Block Engine matching them. Roughly 80 percent of Solana validator stake runs jito-solana in 2026. Tips are paid in SOL to validators and a portion is distributed to JitoSOL stakers — turning MEV into yield for liquid stakers.

What is SUAVE?

SUAVE (Single Unifying Auction for Value Expression) is Flashbots' purpose-built blockchain for MEV. It separates the role of expressing user preferences (intents), executing private auctions (encrypted memory pools and TEE-based execution), and submitting cross-domain settlement to many different L1 and L2s. Two devnets, Centauri and Andromeda, have been live since 2024; the SUAVE mainnet is targeted for late 2026. The thesis is that MEV will become a cross-chain, cross-domain phenomenon and a neutral chain optimised for confidential transactions is the right substrate.

What is an Order Flow Auction (OFA)?

An Order Flow Auction is a market mechanism where users (or their wallets) sell their pending transactions to professional fillers in exchange for better execution and a rebate of any captured MEV. Examples include MEV-Share (Flashbots), MEV-Blocker RPC (CoW DAO + Beaverbuild + Agnostic), CoW Protocol's batch auctions, UniswapX's Dutch auctions, 1inch Fusion, Aori, and DFlow. By 2026 OFAs and intent-based DEXes route over 30 percent of Ethereum DEX volume and have substantially reduced sandwich attacks against retail.

Are MEV-Boost relays censoring transactions?

After the August 2022 OFAC sanctions against Tornado Cash addresses, several MEV-Boost relays (notably Flashbots, BloXroute Regulated, BloXroute Max Profit, Eden) chose to filter blocks containing sanctioned-address transactions. At the peak in late 2022, censoring relays produced 70 percent of blocks. The Ethereum community responded by building neutral relays (Ultra Sound, Aestus, Agnostic, BloXroute Ethical) and tooling like mevboost.pics that publishes per-relay censorship statistics. By 2026 neutral-relay share has climbed back above 65 percent and the censorship debate has largely shifted toward enshrined PBS (ePBS) where credibly neutral block production is built into the protocol.

How can I protect myself from MEV as a normal user?

Use a private RPC with built-in protections. The simplest options for Ethereum are MEV-Blocker (free, run by CoW DAO + Beaverbuild + Agnostic), Flashbots Protect, BlockNative, or any wallet that ships protection by default (Rabby, Brave, MetaMask's "Smart Transactions" backed by MEV-Share). For DEX trades, route through CoW Swap, UniswapX, 1inch Fusion or Matcha — these are intent-based and explicitly designed to refund any captured MEV to you. On Solana use Jito's regional MEV-Protect RPC. Avoid sending large swaps directly to a public mempool, especially during volatile periods.

Glossary

Related reading (internal links)

Sources and further reading

About the author

DeFi Intel Research is the in-house research team behind DeFi Intel, a crypto data and MEV intelligence platform. Our analysts maintain a real-time fleet of 40+ MEV scanners across Ethereum, Solana, and major L2s. We hold no position in COW, JTO, or any other token discussed in this article at time of publication. For corrections or to suggest additions please email [email protected].

Last updated: 2026-04-26

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