Rebuffo’s Background and Early Contributions

Giulio Rebuffo began his work on Ethereum-related client projects as a high school student, contributing to TurboGeth, which evolved into Erigon. At age 17 he earned recognition as one of the youngest core developers in the Ethereum ecosystem. He advanced to principal engineer at Erigon during the 2022 Merge transition that moved the network from proof-of-work to proof-of-stake consensus. By age 22 Rebuffo had become CTO of the client, where he focused on engineering features to improve protocol speed without requiring hard forks.

Rebuffo highlighted adversarial thinking as a key skill for anticipating potential security issues in code before deployment. He previously contributed to ETH_en and Erigon. In his new position he will collaborate directly with the foundation’s technical teams and management.

Leadership Shifts at the Ethereum Foundation

The Ethereum Foundation has faced notable staff departures over the past year. Researchers Julian Ma and Carl Beek left in May 2026. Tomasz Stańczak stepped down as co-executive director in February 2026. In April 2026 Josh Stark and Protocol Guild organizer Trent Van Epps exited. The three heads of the Protocol cluster—Barnabé Monnot, Tim Beiko, and Alex Stokes—also departed or took sabbaticals, with new coordinators filling those roles.

Other changes include the departure of Péter Szilágyi, creator of Geth, one of the most widely used clients, after nearly a decade at the foundation. A former employee filed a legal action in November 2026 against the foundation and co-founder Vitalik Buterin over an alleged wrongful termination.

AI in Ethereum Client Development

Vitalik Buterin, co-founder of Ethereum, has spoken positively about using AI in the network’s development. In March 2026 he described an AI-generated client called ETH2030 as “quite an impressive experiment.” Created in just six days with generative AI models at a cost of $5,750, the Go-based client aligned with the future roadmap.

Buterin has stressed the need to balance AI-driven speed with security, recommending more test cases, formal verification, and independent client implementations. In a May 2026 blog post he noted that rigorous application of formal verification and AI-assisted tools could make code “far more secure than the way programming has been done before.” He views these approaches as important for defending against sophisticated threats to crypto infrastructure.

Foundation’s Budget and Workforce Adjustments

In June 2026 Vitalik Buterin confirmed that the Ethereum Foundation reduced its workforce by 20 percent and plans a 40 percent cut to its overall budget. These measures have prompted questions about the organization’s capacity to advance its development goals.

Rebuffo’s hiring is presented as a way to strengthen technical capabilities, particularly in integrating AI solutions. The appointment is expected to help accelerate and secure client software through collaboration across teams.