SetupI have a project (pynliner, a python module) on github that I never gave much thought about licensing. Today I got an email asking what license it is under because someone wants to use it in their commercial software.My first thought is that I would love to have 2 licenses one that is free for non-commercial use and one for commercial use. So I started researching software licenses... and got very dizzy. Then I realized I may not even be able to use most of them because my module uses several other modules. So I have a few questions about how licenses filter down.My module uses but does not include code under:MIT License BeautifulSoupLGPL3 cssutilsAnd my module uses and includes code under:MIT License soupselect.pyThis is a relatively minor project but I would like to use it as a learning process for the right way to approach licensing.QuestionsIf I include someone else's code then any licenses I use must not break the included code's license correct?Does the same hold true for other software I use but don't include? Am I limited by the MIT License on BeautifulSoup or LGPL3 on cssutils if I use them but don't include the source in my project?editThanks for pointing out the licenses I had missed on cssutils and soupselect.py. Once these were pointed out the rest of my questions really come down to what is allowed within the MIT License since it is the only one over code I have included and whether or not the output of cssutils is free. I'm comfortable with looking these up the rest of the way. Thanks all.
How are my licensing options limited when I use and/or include other projects in my own?
licensing
If I include someone else's code then any licenses I use must not  break the included code's license correct?Correct - you are only allowed to use it or distribute it under the terms of their licence. If you re-use it, you are actually using it under their licence - you aren't re-licencing it - so anything you do must be allowed under their licence.Does the same hold true for other software I use but don't include? Am  I limited by the copyright on cssutils if I use it but don't include  the source in my project?You can use tools, information etc without including them in your project. The test is does your project become a 'derived work' - normally meaning you have included significant IP from that tool in the project you distribute. If you are distributing source code this is unlikely (unless the GPL tool is a code generator) - if you are distributing a binary it might have parts of the tool's library included in it.If using code under the MIT License doesn't prevent me from having  commercial and non-commercial licenses, what permissions would I need  to get from the authors of the the copyrighted cssutils?cssutils is licenced under LGPL. That means you can include it in your own closed source project if you include it as a dynamic library or run-time loaded module such that the user can swap it for their own version.edit: not entirely familiar with cssutils but it seems to also be a css code generator. If you are using it in your app when run by your user, then yes - it is distributed as a runtime loaded python module, that's fine under the LGPL. All you have to do is make the original source available to your users.If you are using it to generate css files which will then be included separately in your project that's a little trickier. The css files may contain parts of the cssutils IP. You should probably check with the authors of csutils, or check for a faq on their site.  The same question comes up with the GPL version of YACC which includes a specific exemption to use it's output freely.Note copyrighted isn't the same as licenced. Everything you create is copyrighted to you (or perhaps your employer) you only need to consider the licence when you want to give it to other people and want to attach conditions to what they can do with it.