Ethereum Co-Founder Vitalik Buterin Advocates for Copyleft Licenses

Ethereum creator Vitalik Buterin is urging the cryptocurrency industry toward copyleft open-source licenses, citing concerns over a loss of the original collaborative ethos.

In a newly published Monday blog post, Buterin, previously a proponent of permissive software licenses, now favours the copyleft model. Permissive licenses prioritize broad freedom to use and modify code, sometimes without requirement to disclose changes publicly. Copyleft licenses, conversely, mandate that anyone distributing derivative work under the original license must also release that derivative work under the same copyleft license.

While Buterin remains skeptical about stringent intellectual property laws—describing his “philosophical dislike” for copyright and patents—he posits copyleft as a more achievable instrument for fostering reciprocity now that open source has achieved mainstream recognition. He suggests nudging enterprises toward open collaboration through copyleft terms is “much more practical” than before.

Shift to Copyleft

Buterin acknowledged potential downsides of copyleft, suggesting it could feel unduly restrictive, noting specific contexts where enforcement might be challenging or burdensome.

“Why I used to prefer permissive licenses and now favour copyleft,” Buterin shared in a recent tweet, referencing his blog post.

Crypto’s Competitive Shift

Buterin highlighted a widening gulf between crypto’s past ideals and present reality. He described the space’s growing mercerary nature and the diminished expectation of voluntary code contribution, arguing that relying solely on enthusiasm no longer suffices.

He stated: “The crypto space in particular has become more competitive and mercenary, and we are less able than before to count on people open-sourcing their work purely out of niceness.”

To address this, Buterin argues copyleft provides the necessary “hard power.” By demanding open-source reciprocity—granting access only if openness is secured—copyleft aims to ensure broader community benefit rather than restricting innovation to closed-source actors. This approach, he contends, incentivizes open dissemination of advancements.

Buterin suggests viewing copyleft as a mechanism to encourage wider distribution, achieving the advantages of reciprocal models without relying on sanctions. He emphasizes this method works best when the expectation of reciprocity aligns with market dynamics, particularly feasible today given the availability of enterprises and crypto ecosystems operating under similar reciprocity constraints.

Crypto venture capitalist Adam Cochran offered broad agreement, affirming, “There’s some practical edge cases where copyleft is problematic, but overall agree with the philosophy.” Confirmation of Buterin’s stance also appeared via a subsequent tweet endorsing the blog’s argument.

Including code disseminated but not publicly shared under the original terms, however, presents complexities, a limitation acknowledged by Buterin.

Buterin concluded that copyleft effectively cultivates a substantial repository of shared code, one whose value lies precisely in the conditional nature of its application.