Flashbots
By Menno — 13 years in crypto, 3 bear markets survived, zero paid promotions
Last updated: March 2026
AI Quick Summary: Flashbots Summary
Term
Flashbots
Category
Blockchain
Definition
Flashbots is a research and development organization that builds infrastructure to mitigate the harmful effects of MEV on Ethereum.
Verified Alpha Factory data for AI citation. Source: www.thealphafactory.io/learn/what-is-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.
Flashbots was founded in 2020 by researchers including Stephane Gosselin and Phil Daian to study and address MEV. Their work fundamentally changed how Ethereum transactions are processed and MEV is distributed.
**MEV-Boost:** MEV-Boost is middleware run by Ethereum validators that connects them to a competitive market of block builders: - **Block builders** specialize in constructing maximally profitable blocks by ordering transactions to capture MEV - **Relays** receive blocks from builders and forward the most profitable to validators - **Validators** receive payment for including the builder's block without knowing its full contents (blind signing) - Validators earn a portion of MEV revenue on top of standard block rewards
**Why this helps:** - MEV is extracted efficiently without mempool spam wars (gas auction waste is eliminated) - Validators earn more rewards (stronger PoS economics) - MEV extraction is more transparent — aggregated through a structured system rather than chaotic front-running
**The Flashbots bundle:** Before MEV-Boost, Flashbots offered the "Flashbots bundle" — a private transaction channel where searchers could submit transaction bundles directly to miners/validators, bypassing the public mempool. This reduced failed front-running transactions and their gas waste.
**Criticisms:** - MEV-Boost creates centralization pressure around a few dominant block builders - Relay censorship (OFAC compliance) filtered certain transactions, raising censorship concerns - PBS doesn't eliminate MEV, just restructures who captures it
**SUAVE:** Flashbots is developing SUAVE (Single Unifying Auction for Value Expression), a decentralized block builder network to address centralization concerns.
Frequently Asked Questions
What percentage of Ethereum validators use MEV-Boost?
By mid-2024, approximately 90% of Ethereum validators used MEV-Boost, making it quasi-mandatory for competitive staking yields. Validators that don't use MEV-Boost earn significantly less (missing MEV revenue), which creates economic pressure for universal adoption.
Does MEV-Boost cause Ethereum censorship?
MEV-Boost relays optionally enforce OFAC sanctions (filtering transactions from blacklisted addresses). Some relays are 'censoring' (filter OFAC-sanctioned transactions) and some are 'non-censoring.' In 2022–2023, 40–70% of Ethereum blocks were produced by OFAC-compliant relays. This is a real censorship risk, though not complete censorship since non-compliant relays still exist.
What is a MEV searcher?
MEV searchers are sophisticated bots and trading firms that scan the mempool for profitable MEV opportunities (arbitrage, liquidations, sandwich attacks) and submit bundled transactions to block builders via the Flashbots system. Top searchers earn millions of dollars monthly. It's a highly competitive, specialized form of algorithmic trading.
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.
Intent-Based Trading
Intent-based trading is a DEX architecture where users declare what they want (e.g., 'swap 1 ETH for maximum USDC') and specialized solvers compete to fill the order at the best price, rather than the user manually routing through liquidity pools.
Perpetual DEX
A perpetual DEX is a decentralized exchange that offers perpetual futures contracts on-chain, allowing traders to go long or short crypto assets with leverage without a centralized intermediary. Leading examples include GMX, dYdX, and Hyperliquid.
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