What license should I use to publish in the app store?

Hi All, I published over 30 widgets. But never got a real answer. Now Mendix is offering even more option…  https://docs.mendix.com/appstore/general/share-app-store-content#adding (Step 9) Is there a guideline what license to use when? Does it imply, when you are using a GPL v3 widget in your project; your project has be open source too? Is there a difference for server side modules or client side widget? Does it have impact on SaaS, or only is you “distribute” your project? What to do, if you want to sell your module or widget with a proprietary license? If someone published a content in the App Store under a incorrect license, and you used it. Who is responsible? Does Mendix collect all license of all used modules and widgets within a project? This might be needed when you distribute your Mendix project as a product.   Please share your thought, even if you are not a layer. Let me know, what do you think? Cheers, Andries    
2 answers

To everyone publishing app store content, please do not use GPL v3 to publish content.


If you have used a GPL component in your software, then your entire software is considered a ‘work based on’ a GPL and, therefore:

  1. You are not allowed to claim patents or copyright on the software. Moreover, you are obligated to display a copyright notice, disclaimer of warranty, intact GPL notices, and a copy of the GPL.
  2. You are not allowed to change the license or introduce additional terms and conditions.
  3. You are under the reciprocity obligation, which means you are obligated to release the source code and all of the rights to modify and distribute the entire code.


This implies if anybody using a widget or module that was published on GPL v3, they Mendix project must be open source and could have the own copy right.

Is this correct?


A quick search amongst recent AppStore apps shows that ApacheV2 is by far the most popular, followed by MIT. Both stating it is open source and copyable as long as you add credentials.

Some wisdom can be acquired reading https://en.wikipedia.org/wiki/GNU_General_Public_License#Copyleft. Indeed it looks like the GPL seems to prohibit using it in within any proprietary software. But would Mendix not have thought of that before they added that option to the dropdown list?

NB. Not a laywer. Hope someone with legal background will respond and give us a definitive answer.