ChooseALicense.com aims to provide accurate, non-judgmental, and understandable information about open source licenses in order to help people make informed decisions about the projects they start, maintain, contribute to, and use.

We catalog select open source licenses with a Jekyll collection (in _licenses). The catalog is used to render ChooseALicense.com and is regularly vendored into Licensee, which GitHub uses to provide a license chooser and license detection, a licenses API, and to display license descriptions and metadata.

License metadata

Licenses sit in the /_licenses folder. Each license has YAML front matter describing the license's properties. The body of the file contains the text of the license in plain text. The available metadata fields are:

Required fields

• title - The license full name specified by https://spdx.org/licenses/
• spdx-id - Short identifier specified by https://spdx.org/licenses/
• source - The URL to the license source text
• description - A human-readable description of the license
• how - Instructions on how to implement the license
• using - A list of 3 notable projects using the license with straightforward LICENSE files which serve as examples newcomers can follow and that can be detected by licensee in the form of project_name: license_file_url
• permissions - Bulleted list of permission rules
• conditions - Bulleted list of condition rules
• limitations - Bulleted list of limitation rules

Optional fields

• featured - Whether the license should be featured on the main page (defaults to false)
• hidden - Whether the license is neither popular nor fills out the spectrum of licenses from strongly conditional to unconditional (defaults to true)
• nickname - Customary short name if applicable (e.g, GPLv3)
• note - Additional information about the licenses
• redirect_from - Relative path(s) to redirect to the license from, to prevent breaking old URLs

Auto-populated fields

The licenses on choosealicense.com are regularly imported to GitHub.com to be used as the list of licenses available when creating a repository. When we create a repository, we will replace certain strings in the license with variables from the repository. These can be used to create accurate copyright notices. The available variables are:

Fields

• fullname - The full name or username of the repository owner
• login - The repository owner's username
• email - The repository owner's primary email address
• project - The repository name
• description - The description of the repository
• year - The current year
• projecturl - The repository URL or other project website

License properties

The license properties (rules) are stored as a bulleted list within the licenses YAML front matter. Each rule has a name e.g., include-copyright, a human-readable label, e.g., Copyright inclusion, and a description Include the original copyright with the code. To add a new rule, simply add it to _data/rules.yml and reference it in the appropriate license.

Rules

Permissions

• commercial-use - This software and derivatives may be used for commercial purposes.
• modifications - This software may be modified.
• distribution - This software may be distributed.
• private-use - This software may be used and modified in private.
• patent-use - This license provides an express grant of patent rights from contributors.

Conditions

• include-copyright - A copy of the license and copyright notice must be included with the software.
• document-changes - Changes made to the code must be documented.
• disclose-source - Source code must be made available when the software is distributed.
• network-use-disclose - Users who interact with the software via network are given the right to receive a copy of the source code.
• same-license - Modifications must be released under the same license when distributing the software. In some cases a similar or related license may be used.
• same-license--file - Modifications of existing files must be released under the same license when distributing the software. In some cases a similar or related license may be used.
• same-license--library - Modifications must be released under the same license when distributing the software. In some cases a similar or related license may be used, or this condition may not apply to works that use the software as a library.

Limitations

• trademark-use - This license explicitly states that it does NOT grant trademark rights, even though licenses without such a statement probably do not grant any implicit trademark rights.
• liability - This license includes a limitation of liability.
• patent-use - This license explicitly states that it does NOT grant any rights in the patents of contributors.
• warranty - The license explicitly states that it does NOT provide any warranty.

License

The content of this project itself is licensed under the Creative Commons Attribution 3.0 license, and the underlying source code used to format and display that content is licensed under the MIT license.