GPLv3 and BSD – Do I Have to Disclose Backend Source?

gpllicensingopen source

I've gone through a couple of Question on GPL here, but all of them are related to the compiled languages, libraries and distribution.

My web project has a backend that is BSD licensed. The front end is a GPLv3 licensed JavaScript framework which renders a background image that doesn't link to anything from the backend and only renders in the web browser.

Am I required to make available the backend code to the public if I use the GPLv3 licensed library? We are not modifying the GPLv3 licensed library, just using it as is.

Update

I've contacted the library author here is his reply:

I am not a lawyer, so all I can say is that The Library is made
available under the GPLv3. Including it as a dependency in a
commercial program does not, to my understanding, violate GPLv3.
Including a modified version of it without releasing the source to the
modified version would.

Best Answer

The GPL is not capable of "infecting" software it talks to over a network, so no, you do not have to disclose your server-side code.

In fact, this is closely related to why the Affero GPL exists:

The GNU Affero General Public License is a modified version of the ordinary GNU GPL version 3. It has one added requirement: if you run a modified program on a server and let other users communicate with it there, your server must also allow them to download the source code corresponding to the modified version running there.

The AGPL does not "infect across networks" either; even this extra condition is only meant to close the "but the user never runs it" loophole for server-side AGPL'd code. So your client-side Javascript library being GPL or LGPL or AGPL or whatever does not create a disclosure requirement for any server-side code. Only if your server-side code was linked to an AGPL library would you have to make it available.

Edit: I just noticed this section in the FSF's GPL FAQ is highly relevant:

Q: A company is running a modified version of a GPL'ed program on a web site. Does the GPL say they must release their modified sources? (#UnreleasedMods)

A: The GPL permits anyone to make a modified version and use it without ever distributing it to others. What this company is doing is a special case of that. Therefore, the company does not have to release the modified sources.

It is essential for people to have the freedom to make modifications and use them privately, without ever publishing those modifications. However, putting the program on a server machine for the public to talk to is hardly “private” use, so it would be legitimate to require release of the source code in that special case. Developers who wish to address this might want to use the GNU Affero GPL for programs designed for network server use.

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