What is a commercial open source license (OSS)? Thorough explanation of the main licenses!

A source code license is a legal arrangement that sets out the rights and restrictions on the use, modification, and redistribution of a program or software. These licenses are used by software developers and copyright holders as a means to determine how to allow others to use their source code.

There are many different types of source code licenses, and they may be allowed or restricted by the license, especially when it comes to commercial use. Below, we’ll take a closer look at the main types of licenses, whether they can be used commercially, and the caveats associated with them.

1. Open Source License

An open source license is a license that allows you to freely use, modify, and distribute source code, but different types of licenses have different specific restrictions and obligations. Learn about typical open source licenses.

1-1. MIT License

• Summary: The MIT license is a very liberal open source license that allows any use, including commercial use. While you are free to modify and redistribute your code, you must include the original copyright notice and a copy of the license when redistributing.
• Commercial use: possible.
• Note: You are required to keep the copyright notation without removing it, but there are no other major restrictions.

1-2. Apache License 2.0

• Summary: The Apache License 2.0 is a license that allows free use, including commercial use. However, it contains patent clauses, and when redistributed, there is an obligation to provide patent licenses and publish amendments.
• Commercial use: possible.
• Note: For commercial use, patent disclaimers must be observed. In addition, when redistributing, it is necessary to provide a license and the following.

1-3. GNU General Public License (GPL)

• Summary: The GPL is called a “copyleft” license, which means that while the code is free to be used and modified, it must be published under the same terms as the original license when modified or redistributed. Commercial use is possible, but the terms of the license must be observed.
• Commercial use: Yes (but if you redistribute it, you are also obliged to publish the modified code under the GPL).
• Note: Derivative works created using GPL-distributed software must be published under the same GPL license (or a later version if noted). This also applies to commercial products, which limits their incorporation into closed-source commercial products.

1-4. GNU Lesser General Public License (LGPL)

• Summary: The LGPL is a license with some relaxed GPL conditions, specifically for libraries. LGPL-licensed software can be used without requiring the linked program to comply with the GPL license, but it is obligated to publish any modifications to the library itself.
• Commercial use: possible.
• Note: If you use it as a library, the linked software does not have to be open source, but if you modify the LGPL library itself, you are obliged to publish the modification.

1-5. BSD License

• Summary: The BSD license is a very permissive license, similar to the MIT license. Commercial use and redistribution are permitted, subject to retaining license and copyright notices.
• Commercial use: possible.
• Note: It is necessary to retain the copyright notice. Other than that, there are few constraints,
  　　　 Depending on the license variant, there are some additional conditions.

2. Proprietary License

A proprietary license is one in which the owner of the software retains all rights and gives the user very limited usage rights. This is often found in commercial software, where users use it under a license, but no modifications or redistributions are allowed.

• Commercial Use: Typically permitted within the scope of the license, but the source code is not publicly available and cannot be modified or redistributed.
• Note: You may only use the software within the scope of the license provided by the developer. Also, be careful, as contract-based restrictions are often strict.

3. Creative Commons (CC) License

Although it is rarely applied to source code, Creative Commons may also be used in some cases. Some CC licenses allow commercial use and some don’t.

• CC BY: It must be commercially available and retain copyright notation.
• CC BY-NC: Copyright reserved, not for commercial use (non-commercial only).

４. Server Side Public License (SSPL) License

• Freely available cases
  • Individuals, businesses, and research institutions download, modify, and use software in-house
  • Commercial use as a local app (without cloud connection (standalone))
  • Incorporating and using it in OSS projects
  • Development and distribution in the OSS community
• Limited cases
  • When offering as SaaS (commercial service via cloud), all management tools and related source code must also be exposed as OSS
  • Or, if you want to offer it as SaaS with private sources, you need to sign a commercial licensing agreement

Precautions for commercial use

1. Understand the scope of the license: You should carefully check whether commercial use is permitted and what the terms are. In particular, if it involves redistribution or modification, you must follow the license details.
2. Be aware of copyleft implications: Copyleft licenses like the GPL oblige you to publish derivative works created using software under the same license terms. Be careful if you are considering using it as a closed source.
3. Patent and trademark clauses: Licenses that include patent clauses, such as the Apache License, may require a waiver to prevent patent infringement.
4. License combination: If you have a mix of licenses in your project, you need to be careful not to let each license conflict with each other. Especially when incorporating open-source code into commercial products, it’s important to ensure that the license you’re using is appropriate.
5. Risk of License Violation: If you engage in commercial use in violation of the license, you risk legal action. Especially for businesses, compliance with licensing terms is also important from a compliance perspective.

When understanding source code licenses and using them commercially, it is necessary to accurately understand the types and conditions of the licenses and take appropriate actions based on them.