I'm considering using this GPL-3.0-licensed library as a development aid in a game. Development builds that include this library (and other unrelated tools) would be used by myself and any parties involved in the development of the game. The library (and the features that use it) would be entirely excluded from production builds intended for the general public.

Would this be allowed under the terms of the GPL? While we're at it, is there precedent for this?

Some facts that may be relevant:

  • The game is proprietary and closed-source and will remain so for the foreseeable future.
  • No other libraries or assets in my game are licensed under the GPL or similar.
  • I use a lot of permissively-licensed (MIT, BSD, public domain, etc.) third-party libraries, but I can provide details if necessary.
  • I have not actually installed or used this library yet.
  • I may someday extract parts of the game's source code into reusable libraries. I don't yet know which parts or under which license I would do so.
  • I don't yet know if I will need to include the library in my game's source repository.
  • I'm the sole developer of this game, but if I had employees then they would have access to development builds. If I hire contractors, they will also have access to development builds.
  • If I work with a publisher or other service provider (such as for marketing or QA), they would have access to development builds. They might or might not have partial ownership of the game and its copyright, but it would depend on the terms of an agreement.

1 Answer 1


Yes, that would be allowed.

Versions of a software product that don't derive from/use GPL code are not subject to the GPL licensing terms, so you can use whatever license ou like for those versions.

If the people using the development builds are all part of the same organisation, which holds the copyright on the project, then there the use of the GPL library is also not a problem, because the code that depends on the GPL library is not being distributed and the restrictions of the GPL only kick in when you distribute code.

If the development builds are being distributed between copyright holders, then you need to investigate which parts need te be under a GPL-compatible license or dual licensed to meet both your objectives of being GPL-compatible for the development builds and closed-source for the production builds.
Adapting the license requires the explicit consent from all the copyright holders.

  • So if my game were funded by a publisher and I shared with them builds as previously described, would this still be allowed? Or would it depend on how the publishing agreement assigns ownership?
    – JesseTG
    Dec 29, 2019 at 20:15
  • @JesseTG, It would be allowed. The terms under which the development builds can be shared depend on the publishing agreement. But I doubt that the publisher would be interested in exercising the rights (and associated obligations) they would get under the GPL license. Dec 29, 2019 at 20:25
  • I'm not interested in forcing a GPL license upon my game in any capacity; I just want to use this tool to fill a particular development need I (and possibly business partners) have, and to share development builds with business partners without any friction.
    – JesseTG
    Dec 29, 2019 at 20:32
  • I believe that is already grey area as the product leaves your premises, thus you are bound by the GPL. But probably ok, depending on contracts Dec 31, 2019 at 7:08
  • @planetmaker Depending on the contracts in what way?
    – JesseTG
    Dec 31, 2019 at 18:40

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