Giulio Rebuffo, previously chief technology officer at Erigon, has joined the Ethereum Foundation to advance the use of artificial intelligence in Ethereum client development. His appointment follows a year of notable staff departures at the nonprofit, which steers the development and support for the Ethereum blockchain ecosystem.
Background: From early contributor to core engineer
Rebuffo began contributing to Ethereum client projects as a high school student, participating in TurboGeth, the initiative that later became Erigon. By the age of 17, he was already recognized as one of the youngest core developers for Ethereum. He later took on the role of principal engineer at Erigon during the major “Merge” transition, which saw Ethereum move from proof-of-work to proof-of-stake consensus in 2022. At 22, he became CTO of Erigon, focusing on designing features aimed at increasing protocol speed without hard fork changes.
In interviews, Rebuffo highlighted adversarial thinking as his most critical skill, noting the importance of anticipating potential attacks on code before it is deployed.
His move to the Ethereum Foundation signals a shift in research priorities towards integrating AI into both tooling and formal verification processes for client software.
Mini dictionary: Erigon is a high-performance Ethereum execution client, designed to be efficient and scalable for running Ethereum nodes.
Leadership changes at the Ethereum Foundation
The Ethereum Foundation has experienced at least eight prominent departures over the past year, altering the composition of its leadership and research teams. Researchers Julian Ma and Carl Beek left in May. Tomasz Stańczak stepped down from co-executive director in February, after less than a year in the position.
April saw the simultaneous exit of Josh Stark and Protocol Guild organizer Trent Van Epps. In addition, the three heads of the Protocol cluster—Barnabé Monnot, Tim Beiko, and Alex Stokes—either left or went on sabbatical. Their roles were filled by Will Corcoran, Kev Wedderburn, and Fredrik, who now serve as cluster coordinators.
Péter Szilágyi, creator of Geth—one of the most widely used Ethereum clients—left the foundation last year after around ten years of service. In November, a former employee initiated legal action against the foundation and co-founder Vitalik Buterin concerning wrongful termination.
| Key Staff Exits (2025-2026) | Position/Role | Date of Departure |
|---|---|---|
| Julian Ma | Researcher | May 2026 |
| Carl Beek | Researcher | May 2026 |
| Tomasz Stańczak | Co-Executive Director | Feb 2026 |
| Josh Stark | Team Lead | Apr 2026 |
| Trent Van Epps | Protocol Guild Organizer | Apr 2026 |
| Barnabé Monnot | Protocol Cluster Lead | 2026 |
| Tim Beiko | Protocol Cluster Lead | 2026 |
| Alex Stokes | Protocol Cluster Lead | 2026 |
AI in client development and Buterin’s vision
Vitalik Buterin, co-founder of Ethereum, has recently advocated for leveraging AI in Ethereum’s software development. In March, Buterin described an AI-generated Ethereum client experiment as “quite an impressive experiment,” referring to Jiayao Qi’s creation of ETH2030, a large Go-based client aligned with Ethereum’s future roadmap, assembled in just six days using generative AI models at a cost of $5,750.
Buterin emphasized that development teams should balance AI-driven gains between speed and security. He recommended increasing the number of test cases, formal verification processes, and independent client implementations to improve code integrity.
In a May blog post, Buterin stated that rigorous application of formal verification and AI-assisted tools could significantly bolster code security and act as a countermeasure against AI-enabled threats targeting crypto infrastructure.
Buterin has written that with proper implementation, AI-assisted verification could make code “far more secure than the way programming has been done before,” viewing it as essential to defending against increasingly sophisticated attacks.
Recent challenges and next steps for the foundation
In June, Vitalik Buterin confirmed that the Ethereum Foundation reduced its workforce by 20% and plans to cut its budget by 40%. These measures have raised concerns about the foundation’s ability to meet its stated development goals for the blockchain.
Despite ongoing questions about executive leadership replacements, the recruitment of Giulio Rebuffo is considered a key move towards strengthening technical development and integrating AI solutions at the Ethereum Foundation. Rebuffo is expected to collaborate closely with client developers and both technical and management teams to accelerate and secure code production.
Rebuffo is set to bridge applied AI with Ethereum client development, taking a hands-on role across teams in pursuit of more robust and efficient software, as outlined in his public statement.
