License Model: Open SourceOpen source software licenses are software licenses that grant any licensee who obtains the software the right to reproduce, modify, prepare derivative works, and distribute copies of the software at no cost. In order to facilitate these rights, the source code – the human readable form of the code – must be available. Open source licenses contain no restrictions on the field of use, with only minor exceptions. There may be no restrictions on the types of technology with which the software may be used to qualify as an open source license.
Open source software licenses may include conditions on distribution, including requiring any modified code or a derivative work to remain under the same license and requiring the licensee to make such source code available. This type of license is often referred to as “copyleft.” Other terms used to describe the requirement to maintain a derivative work under the same license also include “hereditary” or “self-perpetuating,” as well as the more pejorative terms, “viral” or “contaminating.”
Open source licenses flow with the code, providing a direct license from the author or copyright holder to each licensee and requiring no affirmative execution to be binding. These licenses almost always disclaim all liability and offer no warranties for the software.