Fighting MEV Spam Bots Is Vital to Scaling Blockchains: Flashbots

Maximal extractable value, or MEV, has become a problem so severe that it is limiting the ability of major blockchains to scale, according to research group Flashbots.

MEV refers to the maximum profit that validators can extract by including, excluding, or reordering transactions within a block.

A June 16 report by Flashbots’ steward, Robert Miller, argued that spambots are taking up so much blockspace that “at a time when leading networks like Ethereum, its [Layer 2s], and Solana are racing to scale as fast as possible… spectacularly wasteful onchain searching is starting to consume most of the capacity of most high throughput blockchains.”

The result is “chains congested with spam and fees elevated by that spam.”

That’s because spambots are economically rational, with MEV incentivizing them to consume any new blockspace that becomes available or is added.

On the Optimism mainnet, spam bots used about 57% of the gas but paid less than 10% of the fees, he noted.

It’s particularly problematic on Base, Coinbase’s Ethereum Layer 2 network.

Between November 2024 and February 2025, “Base added 11M in [gas per second] throughput and almost all of it was consumed by spam bots,” Miller said. That’s equal to three Ethereum Mainnets worth of capacity, he added.

“The conversation around scaling has been narrowly focused on raw technical throughput for too long,” Miller concluded. “Our findings show that the critical frontier is no longer making blocks bigger. It is using blockspace more efficiently.”

MEV Auctions

Miller said that Flashbots sees a two-part solution: replacing gas-based bidding with programmable privacy and explicit bidding.

Programmable privacy would allow MEV bot operators “real-time access to the transaction flow, while programmatically enforcing restrictions on how they can use that information,” he said. “The system needs to be able to verifiably guarantee that a searcher can only backrun transactions and can’t frontrun, sandwich, or leak private data.”

The second part is to allow MEV searchers “to explicitly bid for transaction inclusion and ordering in an auction… [submitting] a direct, monetary bid for the specific ordering right they are interested in.”

Flashbots has been experimenting with Trusted Execution Environments (TEEs) to give MEV bot operators visibility without giving them the ability to sandwich.

Another solution: Eliminate MEV

MEV “makes DeFi financially less efficient, opens the door wide for malicious actors, puts users at risk of harm, and makes DeFi unpredictable for users,” said Jan Camenisch, CTO at the DFINITY Foundation, a major contributor to the Internet Computer blockchain (ICP), via email.

“It also causes a misalignment of miners, who were supposed to offer a service (decentralized secure compute) and now pervert the chain into a money extraction mechanism—very contradictory to the original goal,” he added.

ICP’s solution is on-chain encryption, which it recently enabled, Camenisch said. It allows users to send encrypted messages directly to smart contracts. This has direct implications for solving MEV: by encrypting trades, users can prevent miners or blockmakers from accessing transaction details, eliminating the opportunity to insert MEV transactions.

Harm Reduction

Michael Repetný, co-founder and CEO of Marinade Labs, was not surprised to see spam bots taking up so much blockspace.

“That’s already the norm in traditional financial markets, where much of the trading is automated,” he told The Defiant via email. “The difference on-chain is that blockspace is limited and highly visible, so when bots and MEV strategies consume large portions of it, regular users feel the impact more directly through higher fees and slower transaction times.”

He argued that the goal shouldn’t be eliminating bots, but rather building systems that minimize the damage they cause.

“On Solana, that means expanding bandwidth and lowering latency so the network can handle much higher volumes of transactions without being as vulnerable to manipulation through transaction ordering,” Repetný said. “There’s also promising research into approaches like allowing multiple validators to propose blocks simultaneously, which can reduce the power any single validator has over ordering and create a more competitive environment that benefits users.”

Threshold Encryption

“While Flashbots’ two-pronged approach is sound, integrating threshold cryptographic infrastructure adds a critical enforcement layer to programmable privacy and auction fairness, helping mitigate spam and reduce structural inefficiencies that undermine scalability,” said Erick Watson, co-founder and CEO of Randamu, in an email to The Defiant.

It can enforce constraints at the protocol level on who can see what, when they can see it and how often they can see it, Watson said.

“This enforces a sort of temporal access control that scales better than gas fees alone,” he said.

Threshold encryption would provide front-running protection without the need for TEEs, said Luis Bezzenberger, head of product at Shutter Network, in an email.

“Privacy-based solutions like an encrypted mempool offer a better path forward… allowing rollups to safely open up their mempools or preventing front-running,” he said.