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Pale Moon (web browser)

Pale Moon
Pale Moon's computer icon: Artistic impression of Earth's moon tinted blue
Screenshot of Pale Moon version 20.3 running on Windows 8, showing English WorldHeritage
Screenshot of Pale Moon version 20.3 running on Windows 8, showing English WorldHeritage
Developer(s) M.C. Straver
Initial release October 20, 2009 (2009-10-20)
Stable release 25.1.0 (November 14, 2014 (2014-11-14)[1])
Development status Active
Written in C/C++
Operating system Windows, Linux, Android, OSX
Engine Gecko
Platform IA-32, x86-64[2]
Available in 85 languages[3]
Type Web browser
Website .org.palemoonwww

Pale Moon is a web browser based on Mozilla Firefox.[5][6] It is available for Linux and Windows platforms and distributed by M.C. Straver.[7] Pale Moon builds on Firefox, optimizing for efficiency of code and aimed at current and modern microprocessors.[8] Pale Moon is available free of charge as open source code archive and freeware binary releases.[4] Because it is based on Firefox this makes most of the available Firefox extensions and plugins compatible with Pale Moon.[9]


  • Features 1
    • Optimization 1.1
    • User interface 1.2
    • Incompatibility with older hardware 1.3
    • Versioning 1.4
  • Relationship with Firefox 2
  • License 3
  • See also 4
  • References 5
  • External links 6


Pale Moon is a modified version of Firefox with the following changes:


Pale Moon makes use of compiler optimizations by using Microsoft C compiler's "/O2" and "/Ox" flags, and also by selection of included or excluded features from Firefox to increase performance of the browser.[11] The resulting browser will not run on particularly old hardware as a result, but "by cutting out support for older hardware, Pale Moon works with an optimized code base that takes full advantage of modern processor instruction sets."[12]

Further performance tuning is achieved by removing uncommonly used functions of Firefox, including accessibility features, parental controls, crash reporter, ActiveX and Active Scripting.[7][13]

These optimization techniques increased the subjective performance of Pale Moon as compared to Firefox.[5][7][14][15]

User interface

The user interface of Pale Moon since version 4.0 substantially differs from that of Firefox. The status bar was re-added by the authors to keep the information provided by web applications and the messages about the current state of the browser accessible yet less intrusive, as well as keeping other status elements that were removed from the Firefox user interface (webpage download progress bar, file download indicator) by bundling an edited version of an open source status bar extension, until version 12, after which that extension was fully integrated into the core of the browser.[16][17] The tab bar in Pale Moon is also preserved below the other toolbars in the application (as opposed to Firefox's and Google Chrome design). The developer also reordered UI controls with a goal to collect the control elements in the same place to improve the user experience from the usability point of view.[18]

Incompatibility with older hardware

Since Version 3.x of the browser (based on Firefox 3.x source code) is maintained separately to provide support for older processors that don't support the SSE2 instruction set, which is required to run Pale Moon versions 4.0 and later.[19] In August 2012, the head developer announced the end-of-life for that legacy Pale Moon browser citing dropped functionality, maturation of the next-generation code and increasing difficulty for back-port security patches (especially issues related to JavaScript).[20]


The browser used to follow Mozilla Firefox's rapid release schedule before 12.0 was released. Subsequent versions are released sticking to the ESR versions of Firefox with additional and independent development on top.[21]

Relationship with Firefox

The user interface of Pale Moon is similar to the Firefox interface before about version 18. It retains full customisability of the toolbars and the option to have no tab bar showing. The developers of Pale Moon oppose the current Firefox development direction, especially the Australis user interface introduced in Firefox 29.[22]


Like Firefox, Pale Moon is released under the Mozilla Public License 2.0 except for parts relating to branding. Unlike Firefox, however, the Pale Moon binaries may only be redistributed under certain conditions.[4] According to the author, this is to prevent the possibility of any confusion with tainted versions. The project's name, logo, and other artwork are the intellectual property of M.C. Straver, and cannot be used in other third party Firefox builds or other related products without the author's prior permission.[13]

See also


  1. ^ Pale Moon Release Notes
  2. ^ Minimum system Requirements at Home Page
  3. ^ "Pale Moon language packs". Moonchild Productions. Retrieved 16 June 2012. 
  4. ^ a b c "Pale Moon redistribution", Official website, retrieved 2012-02-16 
  5. ^ a b Purdy, Kevin (2010-04-14), "Pale Moon Is a Faster Firefox Clone for Windows and Linux",  
  6. ^ "Pale Moon 24.6.2" by Razvan Mihai Asmanow Serea, Neowin, 16 June 2014
  7. ^ a b c Snyder, Bill (2012-01-10), "Pale Moon: The Fastest Browser You've Never Heard Of", Consumer Tech Radar ( 
  8. ^ Firefox Optimized for Windows – Pale Moon Custom Built Browser, TECK.IN, 2011-04-08, retrieved 2012-02-16 
  9. ^ "Pale Moon: Frequently Asked Questions (F.A.Q.)". Moonchild Productions. Retrieved 30 July 2014. 
  10. ^ Pale Moon x64 build
  11. ^ "Pale Moon Home Page", Pale Moon Home Page (Moonchild Productions), retrieved 2013-04-01 
  12. ^ Wilson, Mark (2011-04-06), "Pale Moon 4: Firefox's leaner, meaner twin – and, whoa is it fast", betanews, retrieved 2012-02-16 
  13. ^ a b "Pale Moon: Technical Details", Official website, retrieved 2012-02-16 
  14. ^ Williams, Mike (2011-06-25), "Pale Moon 5 outshines sibling Firefox 5", betanews, retrieved 2012-02-16 
  15. ^ Noyes, Katherine (2011-08-27), "Want a faster Firefox? Pale Moon can help",  
  16. ^ Finalization of the integration of status bar (Part of PM12 official announce in forums)
  17. ^ Pale Moon – Release Notes, retrieved 2012-06-01 
  18. ^ "About the Pale Moon layout in version 4 and later", Official website, retrieved 2012-02-16 
  19. ^ "Pale Moon: AthlonXP", Official website, retrieved 2012-02-23 
  20. ^ End-of-Life announcement for Pale Moon "Legacy" (Official forum)
  21. ^ Pale Moon version numbers (change of plan) – Pale Moon forum (Official post from main developer)
  22. ^ Palemoon FAQ

External links

  • Official website
  • Summary of differences between Firefox stated by the Official
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