Developer(s)Mozilla Foundation and community
Initial releaseFebruary 2006
Final release
41.0.2 / October 15, 2015; 8 years ago (2015-10-15)
Written inC++, XUL, XBL, JavaScript
Operating systemCross-platform
TypeRuntime environment

XULRunner is a discontinued,[1][2] packaged version of the Mozilla platform to enable standalone desktop application development using XUL, developed by Mozilla. It replaced the Gecko Runtime Environment, a stalled project with a similar purpose.[3] The first stable developer preview of XULRunner was released in February 2006, based on the Mozilla 1.8 code base. Mozilla stopped supporting the development of XULrunner in July 2015.[1][2]

XULRunner was a "technology experiment", not a shipped product,[4] meaning there were no official XULRunner releases, only stable builds based on the same code as a corresponding Firefox release.

Software architecture

XULRunner is a runtime that can be used to bootstrap multiple XUL + XPCOM applications that are equal in capabilities to Firefox and Thunderbird.

XULRunner stores a variety of configuration data (bookmarks, cookies, contacts etc.) in internally managed SQLite databases, and even offer an add-on to manage SQLite databases.


Main page: Category:Software that uses XUL

Mozilla Firefox, Mozilla Thunderbird, Nightingale, Songbird, Flickr Uploadr, SeaMonkey, Conkeror, Sunbird, Miro, Joost, and TomTom Home 2.0 ran on XULRunner. Starting with version 3.0, Mozilla Firefox uses a "private" XULRunner,[5] meaning the framework is installed locally in the application directory.

Kiwix, an offline browser for Wikipedia and Project Gutenberg, used XULRunner until 2017.

The Google AdWords Editor used XULRunner[6] until 2010,[7] as did Evergreen ILS, an open-source library automation system.

The fourth version of the video game series Simon the Sorcerer, Simon the Sorcerer 4: Chaos Happens, uses XULRunner.

In addition, the XULRunner package provided access to ActiveX Control functionality previously found in a (now defunct) third-party ActiveX Control built off the Mozilla source code. Applications using this application programming interface (API) may have function with XULRunner installed and registered.

Starting with Lotus Notes version 8.5.1, IBM deployed XULRunner to provide Notes client support for XPages applications.


In January 2014, dropping XULRunner support was discussed by Mozilla developers.[8] In July 2015, Mozilla stopped supporting the development of XULrunner,[1][2] and the community page has been taken down.[9] As of the beginning of 2016, it had been dropped from the package database of most Linux distributions, including Gentoo,[10] Debian,[11][12] and Ubuntu.[13][14]

XULRunner can still be installed separately, and many XULRunner-dependent applications can be switched over fairly easily. Also developing and running XULRunner apps is still possible through Firefox as well as previous or custom builds of XULRunner.[15] However, its disappearance has caused some dependent packages to be removed from package databases.[16]

See also


  1. ^ a b c Deprecation Notice
  2. ^ a b c XULRunner future and ownership: Announcement to XULRunner dev group
  3. ^ "GRE — Mozilla Developer Center". Developer.mozilla.org. Archived from the original on 2012-07-14. Retrieved 2011-02-28.
  4. ^ Benjamin Smedberg. "Re: lifecycle policy for XULRunner apps?". Newsgroupmozilla.dev.planning. Usenet: mailman.909.1309204932.4544.dev-planning@lists.mozilla.org.
  5. ^ "XULRunner:Roadmap - MozillaWiki". Wiki.mozilla.org. 2009-12-01. Retrieved 2011-02-28.
  6. ^ "xulrunner-adwords-editor — Project Hosting on Google Code". Retrieved 2011-02-28.
  7. ^ "Google Code Archive - Long-term storage for Google Code Project Hosting". code.google.com. Retrieved 2018-08-26.
  8. ^ Terminating xulrunner?
  9. ^ Obsolete and defunct XULRunner community site Archived November 3, 2015, at the Wayback Machine
  10. ^ "403415 – (xulrunner) net-libs/xulrunner removal request".
  11. ^ XULRunner decision on Debian
  12. ^ XULRunner on Debian
  13. ^ Ubuntu bug
  14. ^ "Ubuntu-devel discussion". Archived from the original on 2021-05-07. Retrieved 2016-02-10.
  15. ^ Mozilla will stop producing automated builds of XULRunner after the 41.0 cycle
  16. ^ "Kiwix not available on Debian". Archived from the original on 2016-02-15. Retrieved 2016-02-10.