Ethereum’s co-founder Vitalik Buterin has unveiled a groundbreaking project called leanVM, a minimalistic virtual machine designed specifically for zero-knowledge proofs (ZK-proofs). According to Buterin, this innovation could significantly reduce scaling costs and improve performance across the Ethereum network, marking a major step toward long-term decentralization and sustainability.
The lean Ethereum team has been doing a truly amazing job kicking into gear this year, and delivering on all fronts to ensure Ethereum's long-term scaling, decentralization and resilience.
— vitalik.eth (@VitalikButerin) September 6, 2025
I expect all of these ideas will be ready to kick into gear at roughly the same time as… https://t.co/4uimhAZI5N
The leanVM project is optimized for XMSS aggregation and recursion, relying on a four-instruction Instruction Set Architecture (ISA), multilinear STARKs, and advanced cryptographic techniques such as logup-lookups. These improvements allow leanVM to operate far more efficiently compared to Cairo, particularly by lowering the cost of commitments. Currently, the recursion speed stands at 2.7 seconds, but the Ethereum team is aiming to improve performance by a factor of ten, a leap that could fundamentally enhance throughput and lower transaction costs.
Buterin emphasized that Ethereum’s roadmap has already achieved critical short-term milestones this year, but leanVM represents the next layer of innovation. He praised the team for delivering solutions that balance scalability, security, and decentralization. LeanVM’s design philosophy also reflects Buterin’s belief that protocols should be elegant, simple, and sustainable, rather than rushed or bloated with unnecessary code. As he explained, “Protocols are not something to be hacked together for convenience—they are a form of art.”
The lean roadmap intentionally lags slightly behind Ethereum’s immediate scaling upgrades, ensuring it will be ready as soon as the short-term solutions are live on the mainnet. This staggered approach is crucial, as it guarantees that Ethereum’s scaling remains aligned with the zero-knowledge-friendly ISA architecture, creating a robust foundation for future growth without adding infrastructure overhead.
The timing of leanVM’s development coincides with Ethereum’s next major upgrade, Fusaka, expected to launch in November. Together, these advancements could redefine Ethereum’s capacity to handle large-scale adoption, from DeFi protocols and enterprise applications to emerging decentralized AI ecosystems.
Conclusion
The introduction of leanVM underscores Ethereum’s ongoing commitment to long-term scalability and decentralization. By combining cutting-edge ZK-proof optimization with protocol simplicity, leanVM could position Ethereum as the most efficient and resilient blockchain platform for the next generation of decentralized applications. With Fusaka on the horizon and leanVM advancing in parallel, Ethereum is setting the stage for a scalable, secure, and sustainable blockchain future.
