Buterin insists that using “copyleft” open-source licenses will foster more growth
Vitalik Buterin, the co-founder of Ethereum, has recently expressed his strong support for the adoption of “copyleft” open-source licenses in the cryptocurrency industry. In a blog post published on Monday, Buterin explained his shift in perspective on software licensing. While he previously favored a “permissive” licensing approach, which allows free sharing and modification of code, he now believes the industry would benefit from a more restrictive copyleft model.
The main distinction between these two licensing models is that permissive licenses allow users to freely modify and distribute code without obligations, whereas copyleft licenses also require that any derivative works be released under the same open-source terms. This means that anyone using the original code must also make their changes available to the public under the same conditions.
Buterin shared his philosophical opposition to copyrights and patents, emphasizing that sharing data privately between individuals should not be viewed as an infringement on third parties. He argued that, as the crypto space has grown more competitive and less cooperative, the old ideals of voluntary open-source collaboration have faded. According to Buterin, relying on voluntary sharing is no longer sufficient to encourage innovation, and instead, there needs to be a stronger incentive for collaboration through legal obligations like copyleft licenses.
Why I used to prefer permissive licenses and now favor copylefthttps://t.co/aPGhY0Y0kX
— vitalik.eth (@VitalikButerin) July 7, 2025
He believes that copyleft can help ensure that innovation benefits the entire community rather than just a select few entities that operate behind closed-source projects. By creating a larger pool of open-source code that must be shared by anyone building on it, Buterin sees copyleft as a powerful tool to promote fairness and encourage broader dissemination of ideas and resources in the crypto space.
While acknowledging that copyleft can be restrictive in some cases, Buterin contends that its advantages today outweigh the downsides, especially given the evolution of the crypto industry and the increasing need for a more structured approach to open-source collaboration.
