How to dual license my open source software ?

Question

I am working on an ORM in PHP and would like to dual license it:

• One open source license for open source projects
• One commercial license for commercial projects

However, I was approached by an organizer of a "coding fest" which wanted to use my project for an open source coding event. I am not sure if it would be smart to let other developers work on the project as I want to keep the legal right to release it under a commercial license as well as an open source one. How should I handle that ?

PS: The open source license I have chosen is GNU Affero GPLv3 license (AGPLv3).

Answer 1

It's pretty easy to handle this situation. If you're the only person working on the project, you control the copyright to the whole thing, and can dictate the licensing terms, including separate licensing for commercial or open source projects. If you allow contributions from other developers, then get them to either (a) sign the copyright on their work over to you, or (b) agree to your licensing terms when submitting their own contributions.

Answer 2

Java is a well-known project using dual licensing. To have the possibility to publish also commercial licensed Java, you have to sign a contract to commit your patches to back to Sun. See this URL: http://openjdk.java.net/contribute/

Especially interesting for you is the fact, that the contract itself ('Sun Contributor Agreement' SCA http://sun.com/software/opensource/sca.pdf) is licensed under the creative-commons-sharealike license. That allows you to use and change this contract for your needs, as long as you retain the license (CC-SA is similar to GPL, but for documents and data instead of source-code).