Editing Plug-in (computing) (section)

{{short description|Software component that extends the functionality of existing software}}
{{More citations needed|date=September 2019}}
[[File:Mozilla plugins screenshot without subpixel rendering.png|thumb|[[Mozilla Firefox]] displaying a list of installed plug-ins]]
{{Wiktionary|plug-in|add-on}}

In [[computing]], a '''plug-in''' (or '''plugin''', '''add-in''', '''addin''', '''add-on''', or '''addon''') is a [[software component]] that extends the functionality of an existing [[software system]] without requiring the system to be [[software build|re-built]]. A plug-in [[software feature|feature]] is one way that a system can be [[customizable]].<ref>{{Cite web|last=Sterne|first=Jonathan|date=|title=Plug-in {{!}} software|url=https://www.britannica.com/technology/plug-in|access-date=2021-02-05|website=Encyclopedia Britannica|language=en}}</ref>

Applications support plug-ins for a variety of reasons including:
* Enable [[third-party developer]]s to extend an application
* Support easily adding new features
* Reduce the size of an application by not loading unused features
* Separate [[source code]] from an application because of incompatible [[software license]]s