A software license is a legal instrument (usually by way of contract law, with or without printed material) governing the use or redistribution of software. Under United States copyright law, all software is copyright protected, in both source code and object code forms, unless that software was developed by the United States Government, in which case it cannot be copyrighted. Authors of copyrighted software can donate their software to the public domain, in which case it is also not covered by copyright and, as a result, cannot be licensed.
|Free and open (software must have source code provided)||Non-free|
|Public domain||Permissive license||Copyleft (protective license)||Noncommercial license||Proprietary license||Trade secret|
|Description||Grants all rights||Grants use rights, including right to relicense (allows proprietization, license compatibility)||Grants use rights, forbids proprietization||Grants rights for noncommercial use only. May be combined with copyleft.||Traditional use of copyright; no rights need be granted||No information made public|
|Software||PD, CC0||MIT, Apache, MPL||GPL, AGPL||JRL, AFPL||Proprietary software, no public license||Private, internal software|
|Other creative works||PD, CC0||CC-BY||CC-BY-SA||CC-BY-NC||Copyright, no public license||Unpublished|
A typical software license grants the licensee, typically an end-user, permission to use one or more copies of software in ways where such a use would otherwise potentially constitute copyright infringement of the software owner's exclusive rights under copyright.