Ethereum co-founder Vitalik Buterin advocates copyleft to counter tech monopolies

Ethereum co-founder Vitalik Buterin said he is rethinking his long-held preference for permissive software licenses, advocating for broader use of “copyleft” frameworks as open source enters what he described as a more competitive and concentrated era.

In a blog post published on July 7, Buterin explained that permissive licenses such as MIT or CC0 have historically been his choice because they allow anyone to use, modify, and redistribute code with minimal restrictions, facilitating wider adoption.

In contrast, copyleft licenses like GPL or CC-BY-SA require derivative works to be shared under the same terms, including the publication of source code, creating a legal safeguard for openness.

Buterin wrote:

“Historically, I was a fan of the permissive approach. More recently, I am warming up to the copyleft approach.”

The Ethereum co-founder has been much more active in recent months, proposing new ideas and conducting research amid a shift in priorities.

Protecting openness

Buterin said his earlier preference stemmed from two core beliefs: first, that permissive licenses reduced friction for enterprises hesitant to share their own work and second, philosophical opposition to copyright and intellectual property laws.

He said that permissive licensing is the closest practical approach to “no copyright at all,” aligning with his belief that sharing data or ideas should never be seen as theft.

However, he now sees three major factors changing this calculus. The first is that open source has become mainstream across industries, with companies such as Google, Microsoft, and Huawei not only using but also publishing significant projects under open licenses.

In such an environment, copyleft requirements are less of a barrier and can actively sustain openness by ensuring that large firms share improvements back with the community.

The second factor is the changing culture within the crypto industry itself. Buterin described the space as increasingly “competitive and…