I'm developing a CMS, inside it I use many various plugins/addons wich licenses mostly like MIT, GNU, GPL (such as jQuery, nivoSlider, DataTables and so on..). After reading those licenses I believe I can use them inside my CMS and charge users for my CMS.

In my project I have a specific folder where I store all these plugins with their license and all notices. Is this the correct way? Or should I somewhere on my site notice the all plugins Im using with the path where they can be found in my project folder?

What about if I would use my CMS as SaaS? The end users would not have the access to source files so I would not exactly be distributing it. Is it posible?

And lastly, can I protect my own source files with the license? Wouldnt it collide with the other ones? I would like to protect it as much as I can at least in a legal way as I cannot really protect it as all PHP files are easy accessible.

Thank you for any help. Also note that I have read a lot about license, but these are things I would like to confirm or to see if I misunderstood something.


The MIT and BSD licenses allow you to use them as a library and still keep your work under any license you want. The GPL, on the other hand, doesn't allow this. When you use a GPL library, the whole project must be GPL. There is a special version of the GPL, the LGPL (Library GPL or Lesser GPL) which specifically allows to use the library in non-GPL projects.

But the GPL only applies to distribution of software. When you provide the software as a service, you don't distribute the software. That means you do not need to provide the sorcecode to anyone. There is a special version of the GPL, the AGPL (Affero GPL) which closes this loophole and requires you to license the software to anyone who uses it via network.

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  • Awesome, thank you for the input. So basically I should use only plugins which are available under MIT or BSD license (what about GNU?) to keep my own source code protected. Exception is if I would use it as a service, than I can have the GPL addons freely because I wouldnt have to provide the software anyway. I will be very happy if you could add an another comment to this. – Enn Mar 3 '14 at 8:36
  • @RichardŠůstek Just to make sure we are not misunderstanding each other: Are you aware that the "GNU GPL" is one license and there are no separate licenses named "GNU" and "GPL"? – Philipp Mar 3 '14 at 8:39
  • Oh, yeah you are correct I was just looking in my project folder to see what licenses I have and I saw GNU so I thought it could make some difference, now I see it doesnt. To confirm my question I will have to stick with either MIT or BSD license. I should not have any GNU GPL license if I want to protect my code with my own license. Edit: To be precise, I can use Lesser GPL same way as MIT or BSD. (I Smarty comes with this license) – Enn Mar 3 '14 at 8:45
  • @RichardŠůstek The GPL is often referred to as a "viral" license. It is called that way because GPL code "infects" a product and requires to license the whole software and all of its components under GPL. BSD and MIT do not have this problem, because their licenses do not forbid to release derivate works under a different license as long as you give credit. – Philipp Mar 3 '14 at 8:49
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    @RichardŠůstek When you find code without a license attached to it, you have to assume "all rights reserved" (even when that would mean that the uploader voilates the TOS of sourceforge.net) and need to contact the author to negotiate licensing. – Philipp Mar 3 '14 at 8:57

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