Vitalik Buterin announced leanVM as a new step in scaling Ethereum.

Co-founder of the Ethereum network Vitalik Buterin stated that this year the team has made significant progress in ensuring the long-term scalability, decentralization, and sustainability of the network.
According to him, the key milestones in the short-term roadmap are already approaching, and among the new developments, special attention is drawn to the proposal for a minimal virtual machine with zero-knowledge proofs (zkVM) called leanVM.
leanVM is optimized for XMSS aggregation and recursion and uses a four-instruction architecture of the (Instruction Set Architecture, ISA), multi-linear STARKs, and the cryptographic technique logup-lookups, which significantly reduces commitment costs compared to Cairo.
The current recursion speed is 2.7 seconds, but the team aims to improve the metric tenfold.
"The lean Ethereum team has done truly amazing work this year, making progress on all fronts to ensure long-term scalability, decentralization, and sustainability of Ethereum. I expect all these ideas to come to fruition around the same time the short-term scaling roadmap reaches key milestones," emphasized Buterin.
Let us remind you that on May 7, 2025, the Pectra update successfully took place in the Ethereum mainnet.
He also emphasized the importance of simplicity in protocol design:
"I like the emphasis on how few lines of code each element requires. Protocols are not something that is hastily written, leaving garbage for the sake of short-term convenience. Protocols are a work of art. They should look accordingly."
In response to the question about synchronizing roadmaps, Buterin explained that the lean approach is intentionally lagging behind short-term solutions:
"The idea is to ensure that the lean roadmap lags behind the short-term scaling phases so that it is ready precisely when they are all already operational on the mainnet. The essence of ZK-friendly ISAs is to safely scale the network without excessive infrastructure requirements."
Let us remind you that for November of this year, the Ethereum developers have planned to release the next major update called Fusaka.