Flashbot

Flashbot is an auction service developed to minimize the negative factors of MEV

It operates a separate private transaction pool, not a mempool, where transaction information is open to everyone
It is characterized by conducting a sealed bid blockspace based on a First Price Sealed Bid Auction.
Flashbot participants consist of searcher, relay, and miner.

Searcher: These are the entities that compose the optimal block to seize and extract MEV opportunities, mainly MEV bots and a small number of general users who want to be protected from MEV attacks by submitting their transactions privately. Searchers send the transaction with MEV opportunity along with the bid price to the private transaction pool. Since all information is transmitted privately, searchers cannot check each other's transaction details and bid price, and only relayers and miners have access to the information.

*Relayer: The relayer, acting as a middle manager of the auction, verifies the transactions submitted by searchers, selects the most profitable block, and delivers the block header to the miner. After the miner selects the block header, it sends the entire block to the miner. Relayer's transaction verification work includes spam transaction filtering, because searchers use a private transaction pool to get gas fees waived and send transactions indiscriminately or lead to DDoS attacks (the bids replace gas fees) ).

Miner: Receives a block from Relay and creates a block with the highest bid. Miner revenue is generated from searchers' block bids, and searcher's revenue is the total MEV minus bids. Miners need to use an Ethereum client called MEV-Geth to access Flashbot's private transaction pool.

There are two expected benefits of using flashbots: 1) a fair value of MEV priced in the market through a closed auction, and 2) PGA (Priority Gas Auction) can be prevented by preventing searchers from checking each other's bid prices.

Souirce: Xangle, flashbot