Add-on (Mozilla)

<p>For <a href="/facts/Mozilla/FevL9Itn">Mozilla</a> <a href="/facts/Software/RP79lVSW">software</a>, an add-on is a <a href="/facts/Software_component/eW5wvSHC">software component</a> that extends the functionality of the <a href="/facts/Firefox/xez2zv8H">Firefox</a> <a href="/facts/Web_browser/2pfyymLs">web browser</a> and related <a href="/facts/Application_software/YQuj7Kog">applications</a> – although most are <a href="/facts/Browser_extension/jzkeh57V">browser extensions</a>. Mozilla provides add-ons to users via its official add-on <a href="/facts/Website/SAsjJnca">website</a>.
</p><p>In 2017, Mozilla enacted major changes to the <a href="/facts/Application_programming_interface/GMlN4vUr">application programming interface</a> (API) for extensions in Firefox, replacing the long-standing <a href="/facts/XPCOM/42dTP1Xc">XPCOM</a>-based add-on APIs with the WebExtensions API that is modeled after <a href="/facts/Google_Chrome/4INfWq37">Google Chrome</a>'s API. Thus add-ons that remain compatible with Firefox are now largely compatible with Chrome as well. As of January 2024, there are more than 36,000 add-ons and over 495,000 themes available for Firefox.
</p>

Add-on (Mozilla) open-in-new

Add-on (Mozilla)