Editing Software license (section)


{{Short description|Governs the use and/or redistribution of software}}
{{Use American English|date=September 2020}}
{{use dmy dates|date=June 2024}}
[[File:Software_Categories_expanded.svg|thumb|upright=1.2|Diagram of software under various licenses according to the [[Free Software Foundation|FSF]] and their [[The Free Software Definition]]: on the left side "[[free software]]", on the right side "[[proprietary software]]". On both sides, and therefore mostly [[orthogonal]], "free download" ([[Freeware]]).]]
A '''software license''' is a legal instrument governing the use or redistribution of software. 

Since the 1970s, [[software copyright]] has been recognized in the United States. Despite the copyright being recognized, most companies prefer to sell licenses rather than copies of the software because it enables them to enforce stricter terms on redistribution. Very few purchasers read any part of the license, initially [[shrink-wrap contract]]s and now most commonly encountered as [[clickwrap]] or [[browsewrap]]. The enforceability of this kind of license is a matter of controversy and is limited in some jurisdictions. [[Service-level agreement]]s are another type of software license where the vendor agrees to provide a level of service to the purchaser, often backed by financial penalties.

[[Copyleft]] is a type of license that mandates [[derivative work]]s to be licensed under the license's terms. Copyleft licenses exist for free and open-source software, but also for commercial applications like the [[Server Side Public License]] and others.<ref>{{cite web |title=Open Token Compensation License|url=https://license-token.com/ |website=Open Token Compensation License homepage |access-date=26 March 2025}}</ref> The other types of free licenses lack this requirement: for [[permissive license]]s, attribution is typically the only requirement, and [[public-domain-equivalent license]]s have no restrictions. The proliferation of open-source licenses has compounded [[license compatibility]] issues, but all share some features: allowing redistribution and [[derivative work]]s under the same license, unrestricted access to the [[source code]],  and nondiscrimination between different uses—in particular, allowing commercial use.

{| class="wikitable"
!
! colspan="3" | Free and open
! colspan="4" | Non-free
|-
! !![[Public domain]]{{sfn|O'Regan|2022|p=403}} and [[public-domain-equivalent license|equivalent licenses]] !! [[Permissive license]]<ref name=OSIlicenses>{{cite web |title=Licenses |url=https://opensource.org/licenses |website=Open Source Initiative |access-date=12 May 2024 |date=16 September 2022}}</ref>{{sfn|Sen|Subramaniam|Nelson|2008|p=212}} !! [[Copyleft]]<ref name=OSIlicenses/>{{sfn|Sen|Subramaniam|Nelson|2008|p=212}} !! [[Non-commercial activity|Noncommercial]] license{{sfn|Morin ''et al.''|2012|loc=Free and Open Source Software (FOSS) Licensing}} !! [[Proprietary license]]{{sfn|O'Regan|2022|p=394}} !! [[Trade secret]]{{sfn|O'Regan|2022|p=396}}!! Commercial Copyleft
|-
! scope=row | Description
| Waives copyright protection || Grants use rights, including right to relicense (allows [[proprietization]], [[license compatibility]]) || Grants use rights, forbids [[proprietization]] || Grants rights for noncommercial use only. || Traditional use of [[copyright]]; no rights need be granted || No information made public || Grants use rights, but restricts them to certain use cases
|-
! scope=row | Notable software licenses
| PD, [[CC0]]{{sfn|Fagundes|Perzanowski|2020|p=524}} || [[MIT license|MIT]], [[Apache license|Apache]], [[Mozilla Public License|MPL]], [[BSD license|BSD]] || [[GPL]], [[GNU Affero General Public License|AGPL]] || [[Java Research License|JRL]]{{sfn|Davila|2015|p=6}} || [[Proprietary software]] || ||[[Server Side Public License|SSPL]]
|}
{{clear}}