The SPDX License List is a list of commonly found licenses and exceptions used for open source and other collaborative software. The purpose of the SPDX License List is to enable easy and efficient identification of such licenses and exceptions in an SPDX document or elsewhere. The SPDX License List includes a standardized short identifier, full name, vetted license text, other basic information, and a canonical permanent URL for each license and exception. By providing a short identifier, users can efficiently refer to a license without having to redundantly reproduce the full license. License exceptions can be used with the SPDX License Expression operator, “WITH” to identify a license with an exception.
Here are some relevant points about the list:
- ~300 Licenses and exceptions as of July 2016
- Short license identifiers for easy reference (see the identifier column in the figure to the right)
- Exact text of licenses
- Available on SPDX website – URLs won’t change
- License Matching Guidelines – for matching licenses against those included on the SPDX License List
- License Templates denote license text which is optional or replaceable per the license matching guidelines
- Simple expression language for expressing conjunctive and disjunctive licensing.
There are many possible uses of the SPDX License List and its collateral. Here are just a few key ones:
- Use the standardized short identifier anywhere you would display or exchange the identity of an open source license. You can even link back to the SPDX License List for the text of the license. The license list links are immutable and the links will not change, ever. Note: Only use the identifier if the license text you are matching agrees with the text in the SPDX License List per the list matching guidelines. The power of the short identifier is that when you see it, you know exactly what the license text is!
- Use the License List itself for internal reference or processes.
- Use the matching guidelines and templates provided by the SPDX License List to help determine if the license text you see is the license.
None. The License list can stand on its own.
The following links are meant to provide further information to references and resources you may need when working with the license list.
- SPDX License List
- Matching Guidelines – for determining if the license text is the same as the text on the SPDX list.
- Accessing SPDX Licenses – Details how to access the list and its resources programmatically.
The following list is not meant to be exhaustive but to rather give you an idea of what some people/organizations are doing.
- GitHub – GitHub uses the short identifiers from the SPDX License List in thier Licenses API to represent the licensing of a project: https://developer.github.com/v3/licenses/
- Yotta – Yotta projects use the identifiers from the license list and link back to the license list text to represent the licensing of their project: http://docs.yottabuild.org/reference/module.htm
- See more examples