Josh Stark (조시 스타크), a key researcher and project manager at the Ethereum Foundation, is leaving the foundation after 5 years. On April 16, blockchain outlet Cointelegraph reported the exit is seen as the most high-profile departure among personnel losses that followed a foundation leadership reshuffle in the first quarter of 2025.

Stark said on X, formerly Twitter, that he was leaving the foundation. He did not explain the reasons for his departure and drew a line on his future plans, saying he had "no plans". He also said he would take personal time for now to focus on family and friends.

He has been responsible for core research and project management at the Ethereum Foundation, a nonprofit organisation that oversees development of the Ethereum ecosystem. In the foundation's organisation chart, he is classified as 1 of 4 management personnel and is assessed as having been a central figure in the overall operating structure.

The departure is drawing attention as it intersects with an ongoing internal reshuffle at the foundation. A day earlier, another foundation contributor, Trent Van Epps, said he resigned last week, meaning a series of departures by key personnel has emerged in a short period.

The Ethereum Foundation began a sweeping leadership overhaul in 2025 in response to community criticism over its long-term direction. Vitalik Buterin, an Ethereum co-founder, at the time set out key goals of recruiting new talent, decentralisation and protocol development for faster throughput and transaction speeds.

But Buterin drew a clear line on the foundation's role. He said the foundation would not wade into ideological debates or engage in legislative lobbying or represent "vested interests". He added, "This is not what we do, and it will not change," and said those who want a different vision could form a separate organisation.

The foundation also formalised new leadership in March 2025. It appointed Ethereum Foundation researcher Hsiao-Wei Wang (샤오웨이 왕) and Tomasz Stanczak (토마시 스탄차크), who had been chief executive at Ethereum execution client company Nethermind, as co-directors. Stanczak later stepped down in February 2026, and Wang remains on the organisation chart as part of the foundation's management.

Market attention is therefore focused on whether the foundation's overhaul will lead to stability in its personnel structure. Because Stark did not give a reason for leaving, it is difficult to conclude immediately that the foundation's operating direction has changed. But following the 2025 overhaul, a change of co-directors and the departure of a key researcher have come in succession, reaffirming that the Ethereum Foundation's leadership reorganisation is still under way.

After 5 years on the @ethereumfndn leadership team, I’ve decided to step away and pass the torch. I made this decision in early March, and will wrap up my work at the end of April. I’ve made no plans for the future, other than taking a long break to reset and spending time with…