3Scale Founder Steven Willmott and API Evangelist Kin Lane have launched a non-commercial service today called API Commons, a mechanism for the copyright-free sharing and collaborative design of API specifications, interfaces and data models.

Launched at the Defrag conference, API Commons enables developers to share their APIs under standard Creative Commons licenses. The APIs on API Commons are available on GitHub. API Commons is intended to make APIs more accessible by providing ways for developers to set definitions that others can use. In that way, organizations can plug in APIs, knowing how they are supposed to work. Furthermore, developers can fork the API on GitHub, which will create a new version. If it becomes popular, then it has the potential to be more widely used.

Willmott and Lane created API Commons to contend with the proliferation of APIs and provide a way to protect developers from possible copyright issues. Programmable Web, the journal for the API economy, already has more than 10,000 registered APIs in its directory, but there are also thousands of other unregistered APIs that are used in many different ways.

Most people who build APIs use other APIs as a framework for their own service. But each one is slightly different in structure and design, Willmott said. As a result, new custom code has to be written for every new API. Additionally, the copyright question about APIs remains unresolved.

“The proliferation of APIs means proliferation of interfaces,” Lane told me yesterday at Defrag. “And there are copyright issues. If you use another API design – you are in a gray zone.”

API Commons is expected to be most useful for nonprofit, government and open data APIs, but in the long run it will likely also have a role to play for commercial APIs, as well.