Ethereum co-founder Vitalik Buterin on 4 Jul unveiled "Lean Ethereum," a multi-year protocol overhaul he compared in scale to the 2022 Merge from proof-of-work to proof-of-stake. "This IS the third major iteration of Ethereum," Buterin wrote on X, adding the roll out over will span three to four years rather than a single hard fork.
Buterin Frames Lean Ethereum as Third Major Iteration
6 July 2026 - 07:29 CEST
By Oihyun Kim
Buterin published the roadmap following a meeting of Ethereum researchers in Berlin two weeks earlier, with the updated strawmap published at strawmap.org. Client teams had discussed the direction in Svalbard in April.
Core protocol overhaul
Ethereum will change how it checks transactions. Today, every node re-runs each transaction to verify it. The new design will use recursive STARKs (Scalable Transparent Argument of Knowledge), a form of cryptographic proof that lets one party verify a computation without redoing it, as a built-in part of the protocol.
Anything vulnerable to future quantum computers will also be replaced with quantum-safe versions. Redesigning blobs to withstand quantum attacks is now an urgent priority. Blobs are low-cost data containers used by layer-2 rollups, add-on networks that bundle transactions offchain and post them back to Ethereum cheaply. Consensus - the process by which the network locks in new blocks so transactions can no longer be reversed - will be reworked to reach that point faster.
State structure shift
The biggest change is in how Ethereum stores data. This storage, known as state, holds every account balance, token holding and smart contract on the network. Today's flexible storage will be kept but expanded only modestly. Alongside it, a new storage type with tighter rules but far more room will be added.
Ethereum's state runs to roughly 100 GB today; Buterin's illustrative 2030 scenario sketches capacity for roughly 2TB of the old storage alongside 100TB of the new. Rewriting ERC-20 tokens, NFTs and many DeFi (decentralized finance) applications to use the new type is optional but could cut transaction fees by more than tenfold. Privacy also moves from afterthought to first-class design goal.
Ether (ETH) traded around $1,780 on Monday, down 0.3% over 24 hours according to TradingView data.
