Many free and open source software licenses have conditions in them that ban bundling it with proprietary modules, although, in case of the GPL at least, there are some exceptions for drivers and necessary libraries.

Can open source games be published on Steam without violating the licenses?

I know there are some free software available on Steam, such as Blender (using the GNU General Public License), the Godot engine (using the MIT license), and SuperTuxKart (which is currently in Steam Greenlight).

What permissive license is best for publishing on Steam?

  • 1
    \$\begingroup\$ Keep in mind that licensing something under the GPL doesn't forbid you from licensing it under something else that, aside from being bundled with proprietary software, fulfills the requirements. \$\endgroup\$
    – anon
    Mar 26, 2017 at 0:32
  • \$\begingroup\$ @Gnemlock Thanks, yes, the question does sound better this way. \$\endgroup\$ Mar 26, 2017 at 8:53
  • \$\begingroup\$ @QPaysTaxes Are you sure? I'll have to look into that. \$\endgroup\$ Mar 26, 2017 at 8:56
  • \$\begingroup\$ @leo It's your intellectual property. You can do with it as you please. While it's generally a bit silly to rerelease under something else after you've released it under an open source license, there's nothing stoping you. \$\endgroup\$
    – anon
    Mar 26, 2017 at 12:02

3 Answers 3


Can open source games be published without violating the license? Yes; because open source games have been published, and Steam allows it.

Simutrans is a simulation game that is offered through Steam, and advertises itself as open source. It may very well be the only open source game that has currently been published; There is actually a search filter to look for open source games, but games are tagged by the community, so it is not an exclusive list. Warsow is another such game that is currently in Steam Greenlight, but has been published through other means.

Pikalek has brought up one very big example of open source games being available through Steam; many of the older Doom, Quake and Wolfenstein games are available through the Steam store, despite using open source licenses.

While I can not personally comment on why we do not see many open source games, on Steam, I found a comment on Reddit that offers some sound reasoning as to why we do not see many, and other complications that may arise:

Because to put something on Steam there have to be some person who may represent project in relations with Valve and many open source project don't have such people.

Technically license of open source games allow anybody to put their compiled code and assets on Steam even to sell them, but there is open question about trademarks. E.g even if trademark not registered ownership of project name technically belongs it's original creators so likely Valve not going to accept project to Steam if it's use same name, but not submitted by actual developers.

Other question that many open source games licensed under GPL and it's make it harder to use Steam integration as Steamworks SDK is proprietary and can't be linked with GPL'd game executable. In same time Valve don't provide easy way to use Steam-only features (as far as I aware WebAPI it's not exactly what can be used in game).

- SxxxX (posted 16/2/2015 and quoted as written) @ /r/Linux_Gaming : Why are many (free and) open source games not on Steam?

  • \$\begingroup\$ I didn't know about that filter; that's excellent. +1 \$\endgroup\$
    – ashes999
    Mar 25, 2017 at 23:25
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    \$\begingroup\$ The Castle Doctrine (public domain), Tales of Maj'Eyal (GPL) & HyperRogue (GPL) are also on Steam & open source. A number of id Software games available on Steam (Quake, etc) have open source engines. \$\endgroup\$
    – Pikalek
    Mar 26, 2017 at 1:40
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    \$\begingroup\$ @ashes999 But there's only one result. Time to change that! \$\endgroup\$ Mar 26, 2017 at 9:04
  • \$\begingroup\$ That's not a very good filter, it's missing games like store.steampowered.com/app/370070 \$\endgroup\$ Mar 26, 2017 at 22:55
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    \$\begingroup\$ @ashes999, it turns out they are community based. That kinda changes the impression of the tag, itself, so I've added the relevant info to my answer. \$\endgroup\$
    – Gnemlock
    Mar 27, 2017 at 17:58

To answer your question "What permissive license is best for publishing on Steam?", the answer is: What license you chose for your work does not matter.

When you release your work under a license, you still have full ownership of your work. You are not subject to your own license, because you're not licensing your work from yourself, you own it.* There's nothing that stops you from releasing your code under any number of licenses, unless you sign an exclusive contract. Steam doesn't require titles on Steam to be exclusives, so there's no issue there.

To clarify: I'm talking about your ownership of your work. If you release someone else's work, you are subject to their terms.

*You can give away ownership of your work, but that is something very different from making it available under a license.

  • 1
    \$\begingroup\$ But, often FOSS games have multiple contributors in which not all of the work is owned by a single person, which is why the license is important. I believe the question is meant more in a way of what open license ensures that a game can be published without issues when you have multiple contributors and you don't own all the work. \$\endgroup\$ Apr 21, 2017 at 6:48

By what I understand from other answers, if you own all the code, then you are fine. If there are multiple devlopers/contributors, make sure everyone agrees or say outright that you are going to do so.

  • \$\begingroup\$ This answer would be better if it included some evidence, like a reference to specific licence terms, that could give a reader more confidence that this informal agreement is sufficient. \$\endgroup\$
    – DMGregory
    Jul 7, 2020 at 17:05
  • \$\begingroup\$ I was using information from other answers for this question. \$\endgroup\$ Jul 8, 2020 at 13:07
  • 1
    \$\begingroup\$ If you're not adding new information with this answer, then you don't need to post an answer at all - folks can simply read the existing answers. \$\endgroup\$
    – DMGregory
    Jul 8, 2020 at 13:08

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