Flashbots
A research and development organization that created MEV-Boost, enabling validators to auction block space while reducing harmful MEV.
Flashbots — Flashbots is an open research and development organization that builds tools to mitigate the negative effects of MEV (Maximal Extractable Value) on Ethereum. Their flagship product, Flashbots Protect, routes transactions through a private channel to block builders, shielding users from sandwich attacks and front-running.
How It Works
Flashbots Protect operates as a private transaction relay on Ethereum. When you configure your wallet to use the Flashbots RPC endpoint, your transactions are sent directly to a network of MEV-aware block builders instead of the public mempool. These builders include your transaction in blocks without exposing it to mempool-scanning bots.
Flashbots also operates the MEV-Share protocol, which allows users to share a portion of the MEV their transactions generate with searchers and builders while retaining protection from harmful MEV. Instead of losing value to sandwich attacks, users can actually earn rebates from the MEV their order flow creates.
For developers and advanced users, the Flashbots Bundle API allows submitting bundles of transactions that must be executed atomically and in a specific order. This is used by liquidators, arbitrageurs, and protocols that need precise transaction ordering guarantees.
Why It Matters
Before Flashbots, MEV extraction on Ethereum was chaotic — bots would engage in priority gas auctions (PGAs), bidding up gas prices and congesting the network for all users. Flashbots created an orderly off-chain auction for MEV, reducing network congestion and giving regular users a path to avoid predatory MEV entirely.
Flashbots Protect has become a standard recommendation for any Ethereum trader. By simply switching to the Flashbots RPC, users gain front-running protection, revert protection (failed transactions are not included on-chain, saving gas), and access to MEV rebates through MEV-Share.
Real-World Example
A DeFi user adds the Flashbots Protect RPC (https://rpc.flashbots.net) to MetaMask as a custom network. Every subsequent swap on Uniswap or other DEXs is routed privately. When the user swaps 5 ETH for a token, no sandwich bot can see the pending transaction. The swap executes at the expected price, and through MEV-Share, the user may even receive a small ETH rebate from the builder who included the transaction.
Related Terms
MEV (Maximal Extractable Value)
Profit extracted by block producers by reordering, inserting, or censoring transactions within a block.
Read definition Security & PrivacySandwich Attack
An MEV attack where a bot front-runs and back-runs a large swap to profit from the price impact, costing the victim extra slippage.
Read definition Security & PrivacyFront-Running
Placing a transaction ahead of a known pending transaction in the mempool to profit from the price movement it will cause.
Read definition Security & PrivacyAnti-MEV Protection
Tools and techniques to shield transactions from MEV bots, such as private RPC endpoints, transaction bundling, or slippage controls.
Read definition Security & PrivacyPrivate RPC Endpoint
A non-public blockchain node connection that routes transactions directly to validators, bypassing the public mempool and MEV bots.
Read definitionFrequently Asked Questions
Common questions about Flashbots in cryptocurrency and DeFi.
Flashbots primarily operates on Ethereum mainnet. However, the concepts Flashbots pioneered have been adopted across other ecosystems. On Solana, Jito provides similar MEV protection and bundle services. Some EVM Layer 2 networks are also integrating Flashbots-style MEV protection.
No. Using Flashbots Protect is as simple as adding a custom RPC URL to your wallet. MetaMask users can add it in Settings > Networks > Add Network. Once configured, all transactions are automatically routed through Flashbots with no additional steps required.
Flashbots Protect may add a slight delay compared to public mempool submission, typically a few seconds, as it waits for a builder to include the transaction. However, the trade-off is significant MEV protection and revert protection, which usually outweigh the minor latency increase.
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