The developer of popular alternative Solana client Jito on Friday abruptly pulled the plug on its mempool functionality, a key part of its tech stack that had nonetheless enabled a spate of costly sandwich attacks on traders.
Jito Labs said in a tweet Friday that the mempool function would go offline tonight. Mempools are the place where on-chain transactions sit before they’re added to the blockchain. Solana doesn’t have a mempool but Jito’s method for transaction ordering did.
The decision marks a turnabout for Jito, which just two weeks ago un-banned the practice of “front-running” after deeming the restriction unenforceable, according to messages in its Discord server.
Front-running is a layman’s way of describing the practice of “sandwich attacks” in which trading bots take advantage of transactions which have been added to the mempool but not yet executed. Before they get a chance to, 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. Over half of validators used it at last check.
In a statement sent after this article was published, Jito Labs contributor Lucas Bruder said the team “has been attempting to minimize the impact of negative MEV for months now. This includes working with other protocols on advising applications on better UI, notifying applications of MEV leakage, and advising applications on more accurate pricing mechanisms to allow lower price slippage settings.”
“Additionally, we attempted to engineer solutions to reject sandwich bundles, but our solutions became a cat-and-mouse game with MEV searchers,” the statement said. “Ultimately the Jito Labs team views negative MEV, including sandwich attacks, as a drag on the Solana ecosystem, and in the absence of an engineering solution we have made the difficult decision to suspend the mempool. We remain dedicated to providing an additional revenue stream for validators and stakers in addition to making Solana the best execution environment for all users.”
UPDATE (March 9, 2024, 05:15 UTC): Adds statement from Jito Labs.