Why does Mono for Android cost money if the mono project is opensource and therefore everything based on it must be opensource?
Why does Mono for Android cost money if the mono project is opensource and therefore everything based on it must be opensource
monoopen source
Best Answer
There are two "free" aspects to open-source software:
Free as in beer means you don't have to pay for it. Free as in speech means that you have the freedom to examine the source code, make derived works, etc.
Mono is based on four open source licenses, as described here:
The most important aspect of these licenses is the "copyleft" provision in the GPL. The copyleft provision essentially prevents you from using those libraries and code in a proprietary application, and then distributing it to users or customers. Distribution is what triggers the copyleft provision. Licenses such as MIT and Apache that do not have the copyleft provision in them do not prevent you from using the code in closed-source, commercial applications.
Because the class libraries are licensed under MIT, you are not required to obtain a commercial license to write and distribute your own commercial applications, if you can otherwise abide by the terms of the Lesser/Library GPL, which only requires that you provide any source code changes that you make to the GPL libraries in Mono back to the community.
Contributors who contribute code to the Mono project must assign copyright of their code to the Mono project, so that Xamarin can redistribute the code under a different license. This is how they are able to make certain components of Xamarin proprietary, so that they can charge for it. Because Xamarin is the copyright holder for the entire Mono project, they can redistribute their code in any way they see fit.