Vitalik Buterin announced Lean Ethereum: the third era of the network, comparable in significance to The Merge
Ethereum founder Vitalik Buterin has introduced a fundamentally new network development roadmap called Lean Ethereum. According to his assessment, this is the third largest iteration of the protocol, comparable in scale to the historic transition to Proof-of-Stake (The Merge). This program plans to replace virtually every key component of the network.
It is important to understand: Lean Ethereum is not a one-time update, but a set of long-term improvements that will be implemented over 3–4 years. The new roadmap was unveiled after a closed meeting of Ethereum researchers in Berlin, which followed April discussions with development teams.
What is changing in Ethereum
Changes will affect all major layers of the network. Transaction verification will shift to recursive STARK proofs, completely replacing direct re-execution. All elements vulnerable to quantum computing will be replaced with quantum-resistant counterparts.
Buterin specifically highlighted the priority of privacy. It has ceased to be a secondary task and has become a primary goal: when designing new components, developers now directly ask how private transactions without intermediaries will pass through them.
The priority of quantum security has also sharply increased. This adds a huge amount of work—for example, finalizing the quantum-resistant design for blobs, which the team has been working on for several months, has become urgent.
Additionally, the plan includes formal verification of all components for security, a multidimensional gas fee model, and changes in client architecture. According to Buterin, all of this will be done with minimal disruption to existing applications.
The most controversial change and scaling plans
Buterin called the changes in working with the network state the most radical part of the plan. Consensus is forming around one approach: the current state type will be left almost unchanged and will grow moderately. At the same time, new state types will be added—they scale much better but are not suitable for all tasks.
As an example, the Ethereum founder cited a possible network configuration by 2030: 2 TB of the current state type and 100 TB of the new state type. The new format will be well-suited for ERC20 tokens, NFTs, and many DeFi scenarios, but not for complex "central" objects like Uniswap contracts or on-chain order books.
Rewriting applications is not mandatory, but it will be very beneficial. For example, migrating an ERC20 token to the new storage type could reduce fees by more than ten times.
Buterin added that over the next five years, there will be multiple increases in the gas limit, growth in the number of blobs, and reductions in block time. A major gas limit increase is expected with the Glasterdam upgrade. Each scaling step, he said, depends on when it becomes safe to implement.
Cryptalist Analysis: Lean Ethereum is not just another upgrade, but a fundamental architectural overhaul. The emphasis on STARK proofs and quantum resistance indicates that the team is preparing the network for the challenges of the next decade. The hybrid approach to state is particularly interesting: keeping the old type for compatibility and adding a new one for scaling—this is a pragmatic solution that minimizes risks for the current ecosystem but opens the door to radical fee reductions for the most popular use cases.