Can I use a GPL component in my site without having to disclose the sources of my site?

Question

In which of the following situations can I use a GPL component in my website without having to GPL or disclose the source code of my entire site?

1. The component is a JavaScript library that goes into one page.

2. The component is an executable program called by the backend via something like System.run("component.exe").

3. The component is a dynamic link library invoked at runtime by the backend.

4. The component is a static library linked at build time with the backend.

Note that I only intend to use the GPL component to support the features in my site, not to modify or distribute the GPL component for others to use.

Answer 1

The GPL only triggers when you distribute a program that is derivative of the GPL'ed program, e.g. by linking to it. You are free to run a GPL-licensed program without having to accept the license.

• If the GPL'ed program is client-side JavaScript, then you are distributing the GPL'ed code and possibly derivative code to your visitors. You are only allowed to do this in accordance with the GPL. Whether your website is a derivative work of the GPL'ed code depends on what this code is and how you are using it.

  Simple example: you have a single-page web-application. Your JS code uses a GPL'ed widget or library. Therefore, your SPA falls under the GPL and you are required to make your source code available in accordance with the GPL.

• If you are calling a separate executable where that executable is subject to the GPL, you are very likely not creating a derived work.

  Example: Your server invokes the GNU wget command line tool to archive some web page. Since this is an entirely independent program from your code, your server code is not affected by the GPL.

• If you are linking with GPL'ed code dynamically or statically then you can run this combined work, but may only distribute/publish it under the terms of the GPL. Deployment to servers under your control is not distribution.

  Example: Your server-side code builds upon a GPL'ed library. Therefore, your server-side code is a derived work of the GPL'ed code. If you publish your program, you can do so only under the terms of the GPL. Running a publicly available server is not the same as publishing the server program, so you have no further restrictions.

Note that the GPL contains a family of licenses. Different versions of the GPL have different specific details and terminology. But they all share the same spirit. The LGPL licenses are a more liberal variant of the GPL, e.g. they allow you to link to LGPL'ed code under certain circumstances. The AGPL license gives end-users of web applications similar freedoms to end-users of normal applications. When running AGPL'ed software this answer does not apply as you are subject to additional requirements.

Answer 2

Under the GNU General Public License (GPL), you are free to use, modify, and distribute the software, as long as you make the source code available to your users under the terms of the GPL. This means that if you use a GPL component in your website, you will generally be required to make the source code of your entire website available to your users unless you fall under one of the exceptions to this requirement.

Here are a few situations in which you may be able to use a GPL component in your website without having to GPL or disclose the source code of your entire site:

• If the component is a JavaScript library that goes into one page, and you are not distributing the component to your users, you may not be required to make the source code of your entire site available. This is because the GPL only requires you to make the source code available if you distribute the software. If you are only using the component on your own site and not distributing it to others, you may not be required to make the source code available.

• If the component is an executable program called by the backend via something like System.run("component.exe"), and you are not distributing the component to your users, you may not be required to make the source code of your entire site available. As with the JavaScript library, the GPL only requires you to make the source code available if you distribute the software, so if you are only using the component on your own site and not distributing it to others, you may not be required to make the source code available.

• If the component is a dynamic link library invoked at runtime by the backend, and you are not distributing the component to your users, you may not be required to make the source code of your entire site available. As with the other examples, the GPL only requires you to make the source code available if you distribute the software, so if you are only using the component on your own site and not distributing it to others, you may not be required to make the source code available.

• If the component is a static library linked at build time with the backend, and you are not distributing the component to your users, you may not be required to make the source code of your entire site available. As with the other examples, the GPL only requires you to make the source code available if you distribute the software, so if you are only using the component on your own site and not distributing it to others, you may not be required to make the source code available.

I hope this helps!

Answer 3

You do not need to disclose the source code of your website, ever.

You just need to disclose the source code of the Ckeditor if you make any changes to its internal libraries, components, etc.

Even if your users do not use CKEditor if you make any changes to CKEditor you need to make them public, like putting your modified CKEditor source on git.