If I release my software under certain Contributor Agreements, can I give the software the same effect as if I released it under an Open source license? My business partner and I are unsure which to use!

  • If yes, Great!

  • If no, why not? And what other options do I have?

  • What are these contributor agreements?
    – Zizouz212
    Commented Jun 26, 2015 at 18:31
  • I am legally unable to share them with you at this time. Commented Jun 26, 2015 at 18:32

3 Answers 3


Contributor agreements aren't licenses for your software. They are instead like contracts between the main project managers and contributors. It's like the rules of being with us. So, they aren't software licenses. These agreements generally govern things such as:

  • Intellectual Property
  • Ownership

Note: I am not a lawyer, this is my understanding as a long-time participant in the opensource world.

Open source licenses and contributor agreements serve different purposes.

Open source licenses are a grant of permission from the copyright holder(s) of the work to the general public allowing them to use, modify and redistribute the work. Depending on the particular license there may be conditions attached such as requiring derivative works to be released under the same license and requiring source code to be released alongside binaries.

In the absence of evidence to the contrary the default assumption is that copyright of contributions remains with their creators (or their creators employers in the event of a work for hire) and that the contributors are released under the same license as the project that is contributed to. I don't know if this assumption has ever been tested in court but it is the assumption that a substantial proportion of the opensource world works on.

The result is, in a project with lots of contributors and no contributor agreement, the license can become effectively "locked in". To change the license terms would require getting permission from all the copyright holders, some of which may disagree or may simply be impossible to contact.

Contributor agreements are typically used create an asymmetry in the legal relationship. Contributors grant extra permissions to the originators of the project or even transfer copyright completely. This gives the originators of the project the right to release those contributions under other licenses either as part of an overall project re-licensing or in some cases to sell licenses to use the code in ways not allowed by the open-source license.

Such agreements are controversial, on the one side they can make it easier for a project to move with the times and can provide a means of financing development by selling licenses to downstream users who do not want to accept the open-source license terms. On the other side many find the asymmetry goes against the principles of open-source/free software.


Contributor agreements and licenses are both exactly what they say on the tin. Thus, you cannot license a project under a contributor agreement, and you cannot conduct relations with your contributors under a license.

A license defines the terms under which people are allowed to use your product. A contributor agreement defines the terms under which people are allowed to contribute to your product. Of course, as the owner you can accept or reject any changes you like, but the CA defines the accepted baseline by which all contributors are treated, so nobody complains of mistreatment.

  • 'so nobody complains of mistreatment.' unless they think the CA is a bad idea.
    – hildred
    Commented Jul 1, 2015 at 5:22

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