Optimum, a networking startup run by MIT professor Muriel Médard, said Tuesday that its block-propagation software mump2p is now live in production on Ethereum mainnet, and that liquid restaking provider ether.fi requires all 12 of its node operators to use it.
Optimum said the protocol has 16 node operators in total, running roughly 22,000 validator keys with more than 1.4 million ETH staked. The company put that at more than 3% of all ETH staked. Operators named by Optimum include Blockdaemon, Everstake, P2P.org, Stakefish, and Bitcoin Suisse.
According to Optimum, ether.fi had previously left the software optional for operators. Ether.fi had announced a blockspace deal with ETHGas in April.
“We don’t mandate new infrastructure across our entire validator set unless we’re confident it raises the bar for our stakers and for the network,” Rok Kopp, ether.fi’s co-founder and chief growth officer, said in the announcement.
Optimum also gave a dollar figure of about $3.7 billion for what it calls “Total Value Boosted,” a metric the announcement did not define.
Performance claims came from Optimum
Optimum said Ethereum validators lose attestation and MEV rewards when they see a block late, and argued that validators located farther from major hosting hubs bear the biggest cost. Its pitch is a faster route for blocks moving between nodes.
In August, the company wrote that mump2p runs as an added channel alongside Ethereum’s standard gossip network rather than replacing it. It also encodes data with random linear network coding, which Optimum said was co-invented at MIT.
By Optimum’s own early mainnet measurements, blocks arrived 2.42 times faster than with GossipSub, the peer-to-peer messaging protocol used by Ethereum’s consensus layer by default, while arrival-time variance was about 7.88 times lower. The company also said mump2p users got the block first in nine out of 10 measurements.
Those figures were self-reported, and the announcement did not say how they were gathered. The same two multiples appeared in an Optimum-sponsored Four Pillars report in August, which described a test across 30 gateways while the company was still preparing its mainnet integration.
Médard framed the case in trading terms in the announcement: “In traditional finance, firms spend billions shaving milliseconds off execution because speed is money.”
From testnet to production
Optimum ran a private testnet with seven operators in June 2025, two months after raising an $11 million seed round led by 1kx.
The company said connecting is free and permissionless, requires no changes to consensus or execution software, and takes one engineer less than an hour.
In August, however, Optimum described the network as permissioned for now, with operators connecting through an API key issued by the company.
Optimum said it plans to bring the protocol to other high-throughput blockchains after Ethereum.