Permissive Copyleft License
Version 1.0
Copyright © [YEAR] – [AUTHOR]
The Permissive Copyleft License (PCL) is a libre open-source license specifically crafted for both software source code and its corresponding binaries. Unlike licenses that strictly adhere to either purely permissive or rigidly copyleft principles, the PCL is designed as a long-term, balanced solution. It addresses the inherent challenges and potential drawbacks of both extremes: mitigating the risk of pure permissive licenses allowing unchecked proprietary forks that don't contribute back to the community, while avoiding the complexities and potential friction points sometimes associated with overtly strict copyleft licenses. The PCL aims to foster broad adoption and collaborative development by providing a framework that encourages contribution and sharing while remaining highly accessible for diverse use cases.
The Permissive Copyleft License (PCL) draws significant inspiration from the Creative Commons Attribution-ShareAlike 4.0 International license, a well-established and widely understood license primarily used for non-software works. The core principles of CC BY-SA 4.0 have been carefully reinterpreted and reworded within the PCL to specifically address the unique characteristics and requirements of software development and distribution. This adaptation ensures that the fundamental spirit of "attribution and share-alike" is translated effectively into the context of source code and binaries, providing a familiar yet tailored framework for software creators and users.
At the heart of the PCL's philosophy is the belief that the works created by software developers and contributors should be freely accessible and usable by anyone. This commitment to "libre" open source ensures that individuals, smaller organizations, and independent developers can readily benefit from and build upon PCL-licensed software. We envision a vibrant ecosystem where innovation is fostered through open access and collaboration, allowing the best ideas to flourish and propagate throughout the community.
However, while promoting broad accessibility, the PCL also includes carefully considered provisions designed to prevent exploitation, particularly by major corporations who might otherwise leverage freely available code without contributing back or sharing their modifications. The copyleft aspect, inspired by the "ShareAlike" principle of CC BY-SA, requires that derivative works are also licensed under terms compatible with the PCL. This mechanism helps to ensure a more equitable exchange, encouraging reciprocal contributions and preventing a scenario where a few entities profit immensely without feeding back into the open-source community that made their success possible.
The Permissive Copyleft License (PCL) has been meticulously crafted with a dual purpose: to actively encourage and facilitate robust open-source collaboration while simultaneously providing flexibility for companies and individuals who develop proprietary software. Recognizing that a healthy software ecosystem includes both open and closed source components, the PCL is designed to be a bridge between these worlds. Its structure encourages contributions back to the PCL-licensed project for modifications to the core code, fostering a strong collaborative environment for the benefit of the entire community.
The PCL explicitly grants, without any fee or charge, the right to any person or organization who obtains the software licensed under its terms to utilize that software for commercial purposes. This means that individuals, startups, small businesses, and even large corporations are free to incorporate, run, and use the software as part of their revenue-generating activities, whether it's for internal operations, providing services, or building products that are sold for profit. There are no limitations or restrictions imposed by the license based on the user's intent to make money from the software's use.
Furthermore, the PCL grants the right to distribute original and modified copies of the software. This is a cornerstone of open-source freedom, allowing users to share the software with others in its original form or after they have made changes or improvements. This permission facilitates the spread of the software, supports community involvement through sharing of modifications, and enables developers to build upon and enhance the original work. The ability to distribute modified versions is fundamental to collaborative development and the evolution of open-source projects.
Finally, the PCL explicitly permits the private use of the software licensed under its terms. This guarantees that individuals and organizations can download, install, and run the software for their own internal use, whether for personal projects, within a company's infrastructure, or for any purpose that does not involve public distribution or direct commercial offering of the software itself. This ensures that the software is freely available for private exploration, experimentation, and application without the need for external interaction or public sharing.
The broad permissions granted by the PCL, including commercial use, distribution, and private use, are subject to specific conditions that ensure the principles of attribution and share-alike are maintained. A primary condition is that any modifications made to the PCL-licensed software must be clearly documented and subsequently licensed under the same version of the PCL or a later version. This ensures that improvements, bug fixes, and new features developed on top of the original software are contributed back to the community under terms that are compatible with the original license, fostering a continuous cycle of development and sharing. It promotes transparency regarding changes and ensures that the derivative work remains under the PCL's protective framework.
Furthermore, the PCL allows for the use of PCL-licensed software within larger software solutions that may be licensed under a different license, whether it be another open-source license or a proprietary (closed-source) license. This flexibility is a key aspect of the PCL's design, enabling its integration into a wide range of projects. However, this permission is contingent upon two important requirements: the developers of the larger software solution must clearly state their usage of the PCL-licensed software and must distribute any modified versions of the PCL-licensed software itself under the terms of the PCL. This ensures proper attribution to the original PCL project and guarantees that any enhancements made to the core PCL components are made available back to the community, even when used in a proprietary context.
The Permissive Copyleft License (PCL), like most open-source licenses, includes a significant clause regarding the limitation of liability. This provision is crucial for protecting the original authors and contributors of the software. It typically states that the licensors (the creators and contributors of the software) shall not be held liable for any direct, indirect, incidental, special, exemplary, or consequential damages arising from the use or inability to use the software. This includes, but is not limited to, procurement of substitute goods or services, loss of use, data, or profits, or business interruption, regardless of how caused and on any theory of liability, whether in contract, strict liability, or tort (including negligence or otherwise), even if advised of the possibility of such damage. This limitation is essential for encouraging contributions to open-source projects, as developers are providing their work freely and cannot assume the burden of potential legal and financial risks associated with its diverse applications.
In tandem with the limitation of liability, the PCL also incorporates a strong disclaimer of warranty. This clause clearly states that the software is provided "as is," without any warranty of any kind, either express or implied. This includes, but is not limited to, warranties of merchantability, fitness for a particular purpose, and non-infringement. The authors and contributors make no guarantees about the software's performance, reliability, accuracy, or suitability for any specific use case. Users bear the entire risk as to the quality and performance of the software and assume the cost of all necessary servicing, repair, or correction. This disclaimer is a standard practice in open-source licensing, reflecting the nature of freely provided software that has not undergone rigorous commercial testing or quality assurance processes typically associated with proprietary products.