9-7-2025 – Ethereum co-founder Vitalik Buterin announced a fundamental shift in his software licensing philosophy, moving away from permissive open-source licenses toward copyleft frameworks that mandate reciprocal code sharing.
In a Monday blog post, Buterin argued that the cryptocurrency industry has evolved into a “more competitive and mercenary” environment where developers can no longer rely on voluntary code sharing. The change represents a departure from his previous support for permissive licenses, which allow users to modify and redistribute code without requiring them to open-source their derivative works.
Buterin contends that copyleft licensing creates stronger incentives for community-wide innovation by forcing all users to contribute back to the shared codebase. “We are less able than before to count on people open-sourcing their work purely out of niceness,” he wrote, explaining that copyleft ensures benefits reach the entire ecosystem rather than being captured by closed-source projects.
The licensing approach would establish what Buterin describes as a “large pool of code” accessible only to developers willing to share their own source code modifications. Crypto venture capitalist Adam Cochran endorsed the philosophy while acknowledging some practical implementation challenges.
The shift signals growing tension between open-source collaboration and commercial exploitation within the crypto space.