Copyleft for essays, photographs, video, slide decks, datasets, and other creative works rather than for application source. Anyone may copy, redistribute, remix, and sell the material if they credit the creator and, when they share an adaptation, license that adaptation under the same terms. Software Package Data Exchange (SPDX) records the identifier CC-BY-SA-4.0. Creative Commons published the 4.0 international suite on 25 November 2013 as a single global legal code, moving away from the jurisdiction-specific ports that accompanied version 3.0.
The 4.0 public license grants a worldwide, royalty-free, non-exclusive, irrevocable permission to reproduce and share the licensed material and to produce and share adapted material, in any medium or format, including commercial use. Patent and trademark rights are not licensed. The work is offered as-is, with no warranty.
Attribution and ShareAlike
Two license elements set the conditions. Attribution is required whenever you share the material, modified or not. ShareAlike applies when you share Adapted Material you produced.
- Attribution: retain creator identification, copyright notice, license notice, warranty disclaimer, and a link to the source when those are supplied. Indicate if you modified the work, keep a record of earlier modifications, and point to the 4.0 license. Credit must not imply endorsement.
- ShareAlike: the Adapter’s License must be a Creative Commons license with the same elements (Attribution and ShareAlike), this version or later, or a BY-SA Compatible License listed by Creative Commons. You must include the text of, or a link to, that adapter’s license.
- Compatible licenses: Creative Commons has designated the Free Art License 1.3 and GNU General Public License v3.0 (GPL) as BY-SA Compatible Licenses for 4.0. Compatibility with GPLv3 is one-way: you may license contributions to a BY-SA 4.0 adaptation under GPLv3, not the reverse.
- No extra locks: you may not add legal terms or technological measures that restrict rights the license grants. A proprietary End User License Agreement (EULA) that forbids further sharing of a BY-SA remix is such a restriction.
- Cure: rights terminate automatically on breach and reinstate if you cure within 30 days of discovering the violation, or if the licensor reinstates them.
Marketers who remix ShareAlike material have to release the remix the same way. A landing-page rewrite, a translated white paper, a branded infographic, or a training deck that builds on BY-SA text is Adapted Material. Commercial use is allowed. You may not drop ShareAlike and republish the adaptation under Creative Commons Attribution 4.0 International (CC-BY), under Creative Commons Zero 1.0 Universal (CC0), or as all-rights-reserved collateral. Unmodified reuse still requires attribution and a license notice. ShareAlike is not triggered until you share an adaptation.
Attribution-only Creative Commons, a public-domain waiver, and software copyleft draw different lines:
| License | Attribution | Share-alike | Patents and source | Typical use |
| CC-BY-SA-4.0 | Required | Yes: BY-SA 4.0 or later, or a compatible license | No patent grant; no source-code condition | Creative works, Wikimedia text, documentation |
| CC-BY | Required | No. Derivatives may use another license if original attribution is kept | No patent grant; no source-code condition | Maximum reuse of creative works |
| CC0 | Not required | No | No patent waiver | Public-domain dedication with a fallback license |
| GPL | Notices as specified in the license | Strong copyleft on the combined work when distributed | Explicit patent grant; corresponding source required | Software |
Wikipedia and Wikimedia
English Wikipedia and other Wikimedia projects publish article text under BY-SA. That is the ShareAlike corpus a marketing team is most likely to reuse, and the version history matters when you copy from a page.
- 2009: Wikimedia added CC BY-SA 3.0 Unported as the primary text license and kept the GNU Free Documentation License as a secondary license. Implementation on projects began 15 June 2009. GFDL-only submissions stopped being accepted.
- 2023: a Terms of Use update put new Wikimedia edits under CC BY-SA 4.0 (announced 29 June 2023). Older edits remain under 3.0, which already permits adaptations under a later BY-SA version.
- Reuse: English Wikipedia’s copyright policy states that most article text is co-licensed under CC BY-SA 4.0 and the GFDL, and that some imported text is available only under CC BY-SA. Modifications you share must be licensed under CC BY-SA 4.0 or later. A link to the article is commonly treated as sufficient author credit. Each distributed copy needs a license notice. Wikipedia names https://creativecommons.org/licenses/by-sa/4.0/ as a suitable license URL.
- Media: images and other files are not always under the same license as article text. Each file has its own license on its description page. Some are BY-SA, some are BY, some are public domain, and some are non-free. A screenshot of an article still includes the text, which remains BY-SA.
Not a Software License
Creative Commons states, “We recommend against using Creative Commons licenses for software.” The licenses do not require corresponding source, do not grant patents, and are not generally compatible with major Open Source Software (OSS) licenses. Existing software licenses already cover similar reuse rights with terms built for code.
- Docs and assets: documentation, game art, and music remain appropriate CC-licensed material even when they ship beside a program.
- One-way GPLv3 path: the listed compatibility with GPL is a narrow path for BY-SA 4.0 content fused with GPLv3 code so the two cannot be separated. Creative Commons describes that mechanism as not for general use. You cannot license a GPLv3 adaptation under BY-SA.
- Software copyleft: GPL is the copyleft instrument for programs. It requires corresponding source on distribution and includes an explicit patent grant. BY-SA does neither.
- Public-domain tool: CC0 is the Creative Commons dedication CC describes as GPL-compatible and acceptable for software. It still does not waive patents.