CPAL-1.0 – Demystifying the Common Public Attribution License Version 1.0

When it comes to open-source software licenses, the Common Public Attribution License Version 1.0 (CPAL-1.0) stands out as an intriguing option. CPAL-1.0 is designed to strike a balance between open-source principles and the desire for proper attribution. In this comprehensive article, we will delve into the intricacies of CPAL-1.0, exploring its features, implications, and how it affects both developers and users.

Understanding CPAL-1.0:

CPAL-1.0 is a copyleft license that seeks to promote open-source practices while requiring users to provide attribution to the original authors of the software. It is based on the Mozilla Public License (MPL) and shares similarities with other copyleft licenses, such as the GNU General Public License (GPL). However, CPAL-1.0 introduces additional provisions regarding attribution, ensuring that the work’s creators receive proper recognition for their contributions.

Key Features of CPAL-1.0:

a. Attribution Requirements:
Under CPAL-1.0, users who incorporate the software into their projects are required to credit the original authors and provide clear and appropriate attribution notices. This means prominently displaying the names of the original creators, along with any applicable copyright notices, in the distributed code and accompanying documentation.

b. Source Code Distribution:
CPAL-1.0, like other copyleft licenses, mandates the distribution of the source code for any modifications or derivative works based on the original software. This ensures that the open-source nature of the project is preserved, and the community can access and benefit from any improvements made to the code.

c. Copyleft and Licensing Compatibility:
CPAL-1.0 applies a copyleft mechanism, requiring that any modified or derived works are subject to the same licensing terms. This ensures that the openness and freedom of the software are maintained in perpetuity, promoting the collaborative spirit of the open-source community.

Implications for Developers:

a. Recognition and Attribution:
For developers who choose to release their software under CPAL-1.0, this license provides an opportunity to receive proper recognition for their contributions. Users who build upon the original work must acknowledge the developers’ efforts, fostering a culture of appreciation and respect within the open-source ecosystem.

b. Collaboration and Knowledge Sharing:
CPAL-1.0 encourages collaboration and knowledge sharing among developers. By requiring the distribution of source code for modifications, developers can benefit from each other’s enhancements and build upon a shared foundation of code.

c. Compatibility with Other Licenses:
Developers should be mindful of the compatibility between CPAL-1.0 and other licenses. When incorporating CPAL-1.0 licensed code into a larger project, they must ensure that the combined software adheres to the requirements of both CPAL-1.0 and any other licenses involved.

Implications for Users:

a. Proper Attribution:
CPAL-1.0 obligates users to attribute the original authors when using or distributing the software. This ensures transparency and respects the efforts of the developers, fostering a culture of integrity and ethical use of open-source resources.

b. Understanding Copyleft Obligations:
Users must be aware of the copyleft provisions in CPAL-1.0, as any modifications or derived works are subject to the same licensing terms. Consequently, users should be prepared to release their own modifications under CPAL-1.0 when sharing or distributing their versions of the software.

c. Freedom and Community Benefits:
Despite the attribution requirements, CPAL-1.0 still provides users with the freedom to use, modify, and distribute the software. By contributing to the open-source community and complying with the license’s terms, users contribute to the continuous improvement and growth of the shared knowledge base.


CPAL-1.0, the Common Public Attribution License Version 1.0, serves as a unique option among open-source licenses. By striking a balance between open-source principles and the desire for proper attribution, CPAL-1.0 fosters collaboration, transparency, and respect within the open-source community. For developers, it offers an opportunity to receive recognition for their contributions, while users can benefit from a shared pool of knowledge and improvements. By understanding the implications of CPAL-1.0, both developers and users can make informed decisions and contribute positively to the vibrant world of open-source software development.

If you’re interested in exploring a comprehensive list of various open-source licenses and their details, feel free to check out our guide to “Open Source Licenses : A Guide To Software Licensing“. Happy licensing!


  1. “Common Public Attribution License Version 1.0 (CPAL-1.0).” Open Source Initiative
  2. “Choose an Open Source License.” GitHub.

Note: The provided references are for informational purposes and to offer further reading on open-source licensing and CPAL-1.0. Please verify the latest versions and official documentation for any updates or changes to the licenses mentioned.

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