Understanding Open Source Licenses: A Guide for Game Developers

When working on a game development or software project, understanding open source licenses is crucial. These licenses dictate how developers can use, modify, and distribute open source software. In this blog post, we’ll break down the essentials of open source licenses, focusing on the differences between permissive and copyleft licenses, and how they impact the eventual work.

The Basics: Permissive vs. Copyleft Licenses

Permissive Licenses:

Permissive licenses, like the MIT license, are highly flexible and impose minimal restrictions on how developers can use the software. When using software under a permissive license, primary obligations are typically:

  • Including a copy of the license text in the eventual project (usually in a licenses.txt file).
  • Providing attribution to the original authors.
  • These requirements are generally easy to fulfill, making permissive licenses a popular choice for developers who want maximum freedom with minimal legal hassle.

Copyleft Licenses:

Copyleft licenses, on the other hand, are more restrictive. They are sometimes referred to as “viral” licenses because they require that any derivative work (i.e., any project that incorporates or modifies the open source code) must also be distributed under the same open source license. This means the entire project could be subject to the same open source terms, potentially affecting the developer’s ability to commercialize or protect proprietary work or build value in their company.

Notable copyleft licenses include:

  • GNU General Public License (GPL)
  • GNU Lesser General Public License (LGPL)
  • Mozilla Public License (MPL)

Using Open Source Software in Projects

While permissive licenses are straightforward, using software under a copyleft license requires more caution. Here’s how developers can work to navigate these licenses:

Use Tools, Not Code:

Generally, developers can use open source tools like Linux or Gimp without worrying about copyleft requirements, as long as they don’t embed, modify, or directly incorporate their code into the project.

Separate Components:

If developers do use software with a copyleft license, they should keep it as a separate component rather than integrating it directly into the game or project’s codebase. This may help avoid triggering the copyleft obligations. But, this could depend on the scope of the license and the specifics of the use. Developers should tread carefully.

Maintain Documentation:

Developers should always keep a detailed list of the open source components used, along with their respective licenses. This is crucial for compliance and will be helpful during due diligence processes in future deals or partnerships.

Compliance Tips

  • Attribution and Licensing Files: Ensure there is a licenses.txt file that includes all the necessary licenses and attributions for the open source software used.
  • Regular Reviews: Periodically review the licenses of the open source components in the project to stay compliant with any updates or changes in the licensing terms.
  • Consult Experts: If unsure whether a license is permissive or copyleft, don’t hesitate to read up on the license terms or seek advice from legal experts.


In summary, while permissive licenses like MIT are generally safe and easy to use, copyleft licenses require more careful handling to avoid legal complications. By understanding the differences and following best practices for compliance, developers can effectively leverage open source software in projects without jeopardizing proprietary work.

If you have any doubts or need further clarification on open source licenses, feel free to reach out to us for guidance. Happy developing!

Brandon J. Huffman

Brandon is the founder of Odin Law and Media. His law practice focuses on transactions and video games, digital media, entertainment and internet related issues. He serves as general counsel to the International Game Developers Association and is an active member of many bar associations and community organizations. He can be reached at brandon at odin law dot com.

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