According to CoinDesk, Jito Labs, the developer of the popular Solana client Jito, announced on Friday that it would disable its mempool functionality. Mempools are where on-chain transactions are stored before being added to the blockchain. Although Solana does not have a mempool, Jito's method for transaction ordering did. This feature had enabled a series of costly sandwich attacks on traders.
The decision comes as a reversal for Jito, which had recently lifted a ban on front-running after deeming the restriction unenforceable, according to messages in its Discord server. Front-running, also known as sandwich attacks, occurs when trading bots take advantage of transactions that have been added to the mempool but not yet executed. Before the transaction is executed, the bot sandwiches the trade to extract value from the trader. Jito builds and manages an alternative client for processing transactions on the Solana blockchain, with over half of validators using it at last check. Representatives for Jito did not return a request for comment.
