ShareAlike (SA): Definition and Explanation

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Definition

ShareAlike (SA) is a condition found in some Creative Commons (CC) licenses. It requires that any modified, remixed, or adapted version of a licensed work must be distributed under the same or a compatible license as the original.

This condition ensures that all future versions of the work remain equally open and reusable. ShareAlike is considered a “copyleft” mechanism, similar to the principle behind the GNU General Public License (GPL) used in free software.

Key Principle: If you remix, adapt, or build upon a work licensed with ShareAlike, you must release your derivative work under the same license. This keeps the open licensing chain intact and prevents anyone from closing off access to new versions of the content.

Purpose

This license exists to protect freedom, openness, and shared innovation across digital works.

By requiring that every adaptation remains as freely available as the original, the license ensures openness continues. This approach creates an ongoing chain where users and creators can build on existing work without hidden restrictions.

The terms prevent proprietary lock-in by blocking anyone from applying stricter rules or adding digital restrictions like DRM. Once a work is free, it must stay free for everyone who receives it.

Collaboration thrives because contributions, improvements, and fixes must remain accessible to the public. This ensures that everyone benefits from shared knowledge and collective progress.

Working Principles of ShareAlike

The ShareAlike condition lets people build on a work freely, but it requires that any adaptations stay just as open. This keeps creative projects from becoming locked behind stricter rules later.

Permitted Actions

You can modify, remix, and adapt the original work however you like. Changing parts of it, combining it with new ideas, or transforming it into a different format are all allowed.

You can also redistribute your adapted version for any reason, whether for personal use, public sharing, or business purposes.

If the original license allows commercial use, like with Creative Commons Attribution-ShareAlike (CC BY-SA), you are free to use the adapted work for profit too.

Conditions (What You Must Do)

You must apply the same license or one that is legally compatible to any new version you create. This ensures that the openness of the original continues through every adaptation.

You must keep your adapted version freely accessible and reusable for others, without hidden restrictions or paywalls.

Adding digital locks, restrictive terms, or conditions that prevent free sharing is not allowed under ShareAlike rules.

Restrictions

You cannot apply a more restrictive or incompatible license to your adapted version, even if you made significant changes.

You cannot mix the original work with other materials that introduce restrictions or that break the ShareAlike requirement, because that would limit how others can use and share the result.

When ShareAlike Applies

The ShareAlike condition only applies when the license includes “SA” in its name. You can find it in licenses like CC BY-SA (Attribution-ShareAlike) and CC BY-NC-SA (Attribution-NonCommercial-ShareAlike). These licenses make sure that every adaptation stays open and free for others to use.

If you create a new work based on something licensed under CC BY-SA or CC BY-NC-SA, you must share your version under the same or a compatible license. This rule keeps the sharing chain unbroken.

Licenses without “SA” in their name, such as CC BY, CC BY-NC, or CC BY-ND, do not have a ShareAlike requirement. You can modify or remix works under those licenses without needing to apply the same terms.

ShareAlike helps protect creative freedom by making sure that openness travels with every new version. It encourages a community of sharing, reuse, and collaboration without adding new restrictions.

Example scenarios:

Adding NonCommercial (NC) or NoDerivatives (ND) restrictions to a ShareAlike work violates the license. The derivative must match the SA terms exactly.

ShareAlike vs. Non-ShareAlike Licenses

Understanding the difference helps determine when and how SA applies.

Without SA, users can relicense adaptations however they choose, even as proprietary. With SA, adaptations must remain open.

Why Use ShareAlike?

ShareAlike licensing protects creative freedom and keeps knowledge, culture, and innovation open for everyone. It gives creators and communities a way to share work without fear of it becoming restricted later.

For Creators

Creators use ShareAlike to make sure that future versions of their work stay freely accessible to the public. No one can take an open project, change it, and then lock it behind a paywall or stricter license. Using ShareAlike also shows a strong commitment to the commons, the idea that knowledge and creativity should stay available for everyone.

For Communities

Communities benefit from ShareAlike because it helps projects grow through collaboration. Everyone who contributes knows that their work, and any improvements to it, will remain open and usable by others. This model especially supports educational, civic, and artistic projects that depend on shared resources and mutual reuse.

Who Uses It?

Wikipedia uses a ShareAlike license (CC BY-SA) for all its text content, which allows anyone to use, adapt, and share information as long as they keep it open. OpenStreetMap relies on a similar approach with the Open Database License (ODbL) to protect and share its mapping data.

Many open educational resources (OER) projects also adopt ShareAlike licenses to make learning materials available to teachers, students, and communities without restrictive barriers.

Challenges & Limitations

ShareAlike promotes openness and sharing, but it can also create practical and legal challenges in certain situations. Creators and users need to understand these issues to apply the license correctly.

License Compatibility

ShareAlike content cannot mix with content under more restrictive terms. For example, you cannot combine a CC BY-SA work with a CC BY-NC or CC BY-ND work because their conditions conflict. This makes careful planning important when creating projects that use multiple sources.

Commercial Confusion

Not all ShareAlike licenses allow the same uses. CC BY-SA permits commercial use, while CC BY-NC-SA blocks it. Users sometimes misunderstand what they can and cannot do, especially if they are working with different versions of ShareAlike content.

International Enforcement

Enforcing the ShareAlike condition can be tricky across different countries. Legal systems may interpret Creative Commons licenses differently, and some regions still lack strong case law that clearly defines how courts will handle licensing disputes.

How to Comply with ShareAlike

Following ShareAlike terms is straightforward if you release your new work properly. The key is to match the original license and make sure that anyone who uses your adaptation can enjoy the same freedoms.

Step 1: Identify the license of the original work. Check if it is something like CC BY-SA 4.0 or another ShareAlike version, so you know exactly what rules apply.

Step 2: Use the same license for your adapted work. ShareAlike requires that you do not apply a more restrictive or incompatible license to your version.

Step 3: Include proper attribution. Credit the original creator, provide a link to the license, and clearly indicate if you made any changes.

FAQs