At DuraSpace, we believe in the power of “open”, and strive for transparency and collaboration in everything we do. In alignment with our mission, we work directly with major universities and partners throughout the world to build and maintain software products that provide enduring access to our collective digital heritage.
Achieving that goal also requires providing enduring access to the software that manages, preserves and disseminates that digital heritage. This is why we ensure all our software products are freely available and distributed under permissive (non-copyleft) , open source licenses.
While we see benefit in the usage of any Open Source Initiative (OSI) approved open source license , we require a permissive (non-copyleft) open source license, such as Apache License 2.0, MIT license or BSD-based licenses, for all DuraSpace products.
To support a global community and ensure the longevity of our software products, we feel it is important for service providers and commercial partners to have the freedom to customize or extend our platforms and redistribute or sell such extensions under different licenses or in binary form. Strong copyleft licenses  (such as GPL) require any customizations or redistributions be licensed under the same license, and therefore limit the ability to sell software add-ons or extensions . Finally, because of incompatibility between permissive and copyleft licenses , we avoid distributing our products with any third-party software or libraries that utilize strong copyleft licenses.
Projects or products that wish to align themselves with DuraSpace or be used within DuraSpace products should consider adopting a permissive (non-copyleft) open source license. Examples include Apache License 2.0, MIT license or BSD-based licenses. We’ve provided resources below which may help you with your selection.
- https://choosealicense.com/ provides an excellent overview of why you might choose different types of open source licenses. Permissive licenses are those which do not include the “Same License” condition at https://choosealicense.com/licenses/
- https://opensource.guide/ provides general resources and guides for getting started in open source software. Also includes an excellent overview of the legal side of open source software: https://opensource.guide/legal/
 Permissive (non-copyleft) license definition: https://opensource.org/faq#permissive
 OSI approved licenses: https://opensource.org/licenses
 Copyleft license definition: https://opensource.org/faq#copyleft
 This incompatibility is best described in the Apache Foundation’s statement regarding the incompatibility between the Apache License 2.0 (a permissive license) and GPL (a strong copyleft license): https://www.apache.org/licenses/GPL-compatibility.html