Vitalik Buterin Outlines Multi-Year “Lean Ethereum” Roadmap After Berlin Research Meeting

Ethereum co-founder Vitalik Buterin said Ethereum researchers recently met in Berlin and updated the protocol’s long-term development roadmap, describing “Lean Ethereum” as a phased set of upgrades to be implemented over the next three to four years.

According to ChainCatcher, Buterin said the effort is not a single upgrade but a series of changes comparable in importance to “the Merge,” and would involve refactoring across most core protocol modules.

Buterin said the plan includes changes to verification by introducing recursive STARKs as a core layer-1 component to replace the current direct re-execution approach. He also said quantum security has been elevated in priority, with plans to replace all quantum-vulnerable components and ongoing work on a quantum-secure blob design.

On the consensus layer, Buterin said the roadmap aims to decouple the availability chain from finality to achieve one- to two-round finality, targeting improved security and lower latency.

For the state layer, he said Ethereum’s existing dynamic state would remain, while adding new state types designed for greater scalability, citing examples such as UTXO storage and ring buffers. He added that by 2030 Ethereum is expected to have 2 TB of dynamic state plus 100 TB of new state, and that migrating applications such as ERC-20 tokens and NFTs could reduce gas fees by more than 10 times.

Buterin also said privacy is being elevated from an add-on feature to a layer-1 objective spanning areas such as the mempool and state tree design. For the virtual machine, he said Ethereum may introduce leanISA or RISC-V alongside the EVM, with a long-term goal of making the protocol layer “only direct.”