Using GPL 3rd party code for internal closed source project

Question

If I use GPL software in my internal/closed source app do I have to make the source publicly available? say on the Internet?

Solution 1

This question is specifically addressed in the GPL FAQ, and it says you're allowed to use GPLed software inside a company without legally distributing it. You have no obligation to release either source or binary outside the company.

You're talking about what Richard Stallman (the person behind the Gnu movement) calls "private software". For private software, any license that allows you to use the code works, because you're not distributing it. Both the Free Software Foundation and the Open Source Initiative maintain that it should always be possible to use software privately.

Solution 2

Loosely speaking, the GPL requires that you offer to make the source code available to whoever you make the binary available to. If the application is only for internal use, then this is probably not a problem, since you are presumably not worried about your internal users requesting or using the source.

Edit: Note that, to comply with the GPL, you're still obligated to offer the source code (even if no one takes you up on your offer), and you could conceivably get into dicey territory if an internal user insists on getting a copy of your source and you're not ready to give them one.

Edit: I did not realize that the GPL FAQ specifically excludes internal use from being considered distribution, which makes David Thornley's answer much better than mine. I guess I'll leave my answer since it covers the broader issue of limited distribution.