The Situation: I am developing a library for iOS which can be used on the iPhone, iPod Touch and the iPad. I would like to distribute it for non-commercial use under an Open Source license and for commercial use on a pay-per-use basis.
Issues: Commercial use consists of using the library in (i) in-house projects and (ii) in software submitted to Apple's app-store. I have difficulties in properly defining case (i) and I wonder how to cover such a case at all (any advice is appreciated). However, point (ii) is clearly defined and the license scheme should allow me to charge money for apps deployed on Apple's app store.
There are a couple of discussions on this board about dual-licenses, but none of them covers potential pitfalls (if there are any) of deploying on Apple's app store. Are there license compatibility considerations that I need to be aware of? In any case, several posters have discouraged people from attempting to write their own new license.
Update on licensing options:
A. Creative Commons: It seems that there are licenses which allow non-commercial use, but forbid commercial use and derivatives. Specifically, the Creative Commons License has an option/a variant which forbids commercial use. In the case of software this could at least in principle forbid in-house developments. On the other hand, their FAQ page discourages use of this license for software. However, I did not find any similar option/variant in the specific case of software licenses, see e.g. this comparison of software licenses where the discussion of licenses preventing in-house use is explicitly excluded.
I have come across this very interesting thread which elaborates on such considerations. Basically the use of such a “I don't want you to make money”-clause is discouraged. Apart from the questionable attitude in itself there is the problem of enforcing those regulations, making such an option appear impractical.
B. QPL: I have also looked into the QPL license, but I am not sure if it is suitable. In particular, it seems that software needs to be distributed as Open Source if it was developed prior to buying a license (see the FAQ here, see also this thread). This is not what I want, but it may not be a problem of the QPL specifically but rather caused by the GPL used in contemporary code; or it might even be a generic drawback of all dual-license models that involve Open Source. Furthermore, I find the language regarding the entry on “non-free software for internal use” hard to comprehend - it touches the issue of when in-house solution become “commercial” which already bit me above.
Questions:
- Does the Creative Commons license indeed forbid “commercial in-house” use? Is there an equivalent license for software?
- Is there a commercial license applicable for libraries used on mobile devices?
- Is there already a combination of licenses that might work in my case?