Pale Moon
Developer(s)M.C. Straver[1]
Moonchild Productions[2]
Initial releaseOctober 4, 2009; 12 years ago (2009-10-04)
Stable release[3] Edit this on Wikidata / 11 November 2021; 12 days ago (11 November 2021)
Written inC++, C, JavaScript
EnginesGoanna, SpiderMonkey
Operating systemWindows 7 or later, Linux (contributed builds for various platforms[4])
PlatformIA-32, x86-64[5]
Available in37 languages[6]
List of languages
Arabic (ar), Bulgarian (bg), Traditional Chinese (zh-TW), Simplified Chinese (zh-CN), Croatian (hr), Czech (cs), Danish (da), Dutch (nl), American English (en-US), British English (en-GB), Filipino (tl), Finnish (fi), French (fr), Galician (gl), Greek (el), Hungarian (hu), Indonesian (id), Italian (it), Icelandic (is), Japanese (ja), Korean (ko), Polish (pl), Brazilian Portuguese (pt-BR), European Portuguese (pt-PT), Romanian (ro), Russian (ru) Argentine Spanish (es-AR), Mexican Spanish (es-M), Serbian [cyrillic] (sr), Castilian Spanish (es-ES), Slovak (sk), Slovenian (sl), Swedish (sv-SE), Thai (th), Turkish (tr), Ukrainian (uk)
TypeWeb browser
News aggregator
License Edit this on Wikidata

Pale Moon is an open-source web browser with an emphasis on customizability; its motto is "Your browser, Your way".[8] There are official releases for Microsoft Windows and Linux,[8] as well as contributed builds for various platforms.[4]

Pale Moon originated as a fork of Firefox, but has subsequently diverged. The main differences are the user interface, add-on support, and running in single-process mode. Pale Moon retains the highly customizable user interface of the Firefox version 4–28 era.[9] It also continues to support some types of add-ons and plugins that are no longer supported by Firefox,[10][11] including NPAPI plugins such as Flash Player.[12][13]


Pale Moon 8 running on Windows XP (no longer supported)
Pale Moon 8 running on Windows XP (no longer supported)
Unbranded logo
Unbranded logo

Pale Moon has diverged from Firefox in a number of ways:

Old platforms

Version 25.7.0 was the final release to actually support Windows XP.[19] Version 27.9.4 was the final official release to support Windows Vista as well as the final unofficial release for Mac OS X 10.6 Snow Leopard.[20]

The end of XP support was quickly followed by Pale Moon getting at least two forks of its own, both of which take the most recent Pale Moon code and recompile it for XP; New Moon by roytam1, and Mypal by Feodor2.[21]

The Pale Moon developers have since forced Feodor2 to discontinue Mypal over a license technicality.[22]

The final version for Snow Leopard is the foundation for the Arctic Fox web browser.[23]

The official releases do not support older processors without the SSE2 instruction set.[5] However, a contributed build for Linux was available that supported some older processors, but it has since been discontinued.[24][25]


Pale Moon's source code is released under the Mozilla Public License 2.0 except for parts relating to branding. To ensure quality, redistribution of officially branded Pale Moon binaries is only permissible under specific circumstances.[7] The name and logo are trademarked by the project founder and cannot be used without his prior permission.[26]


This section may be too technical for most readers to understand. Please help improve it to make it understandable to non-experts, without removing the technical details. (April 2020) (Learn how and when to remove this template message)

M.C. Straver is the project founder and lead developer.[1] Straver's first official release of Pale Moon, in 2009, was a rebuild of Firefox 3.5.2 with tweaked compiler settings.[jargon][27] Eventually the scope of the project grew, and version 24 became a true fork of Firefox 24 ESR.[27] Starting with version 25, Pale Moon uses a completely independent versioning scheme.[28]

Pale Moon 27 (codenamed Tycho) was a major re-fork of the core browser code to Firefox 38 Extended Support Release, which added HTTP/2, DirectX 11, MSE/DASH, and JavaScript ES6 capabilities.[29] Add-on support remained almost entirely unchanged, with a slight reduction of Jetpack compatibility.[9][30]

Since September 2021 preview (unstable) releases are no longer distributed.[31] The publishing of source code has also been reverted to a cathedral-style of tarballs upon release of binaries, instead of a publicly-available repository.[32]


In 2017, the team behind Pale Moon began the Unified XUL Platform (UXP) project. UXP is an actively maintained fork of XUL forked from Firefox 52 ESR.[33] Straver created a new browser, Basilisk, as a "reference application" for developing UXP.[34][35] Basilisk uses Firefox's Australis user interface (versions 29–56) and is still in active development as of October 2021.

Pale Moon 28, released in August 2018, was the first version built on UXP, thereby providing improved support for web standards and video.[36]


Pale Moon for Android was a distinct development effort that is no longer maintained.[37] First released in 2014,[38] Straver announced the following year that it would likely be abandoned due to lack of community involvement.[39] The final release was 25.9.6.[40]

Mac OS

Unofficial builds existed for macOS.[41]

On 10 March 2021 all Apple Macintosh support was dropped due to lack of consistency from community developers for the Mac platform.[42]


On 31 March 2021 Brian Smith released a fork for macOS called White Star.[43]


In 2013, Pale Moon was a bit slower than Firefox in the ClubCompy Real-World Benchmark, with the browsers respectively scoring 8,168 and 9,344 points out of a possible 50,000.[44] In a 2016 browser comparison test by Ghacks, Pale Moon version 25 had the smallest memory footprint after opening 10 different websites in separate tabs.[45] However, in the same report Pale Moon scored bottom in the Mozilla Kraken, Google Octane, 32-bit RoboHornet tests and second-to-last in the 64-bit RoboHornet benchmarks. Whilst other browsers hung during some tests, Pale Moon only hung during the JetStream JavaScript benchmark.[45]

Current (UXP) versions of Pale Moon score comparatively to other browsers in benchmarks, showing, for example, no significant difference on the Sunspider benchmark compared to Firefox Quantum.[citation needed]

Straver has remarked that the role of benchmark tests is questionable, stating that they "can't be used to draw hard (or regularly even any) conclusions. Plain and simple: they are an indication, nothing more. They serve well if you compare closely related siblings (e.g. Firefox and Iceweasel) or different builds of the exact same browser, to get a relative performance difference between the two on the limited subset of what is actually tested, but that's about as far as it goes."[46]

The questionable role of benchmarking was later confirmed by leading technology experts[47][48] when, for example, Google announced it was retiring its Octane benchmark in 2017,[49] and Mozilla indicating that they "believe these benchmarks are not representative of modern JS code" when introducing WarpBuilder in November 2020, admitting that their new technology "is currently slower than Ion on certain synthetic JS benchmarks such as Octane and Kraken".[50]

Market share

This section needs expansion. You can help by adding to it. (May 2021)

Worldwide market share according to StatCounter was stable at 0.02% between March 2019 and 2020.[51]

Data breach incident

It was reported on 10 July 2019 that a data breach of the archive server holding previous binaries of the Pale Moon browser had occurred and malware inserted into the executables. This breach was discovered on the previous day. It is unknown when the breach first occurred. At first, it was estimated to have been as early as 27 December 2017, according to timestamps. After getting some more feedback from users, it is now estimated to have occurred somewhere between April and June 2019.[52]

See also


  1. ^ a b M.C. Straver. "About Moonchild Productions". Archived from the original on 13 March 2017. Retrieved 19 April 2018.
  2. ^ M.C. Straver. "About Moonchild Productions". Archived from the original on 9 April 2020. Retrieved 23 April 2020.
  3. ^
  4. ^ a b "Contributed builds of Pale Moon". Pale Moon. Retrieved 12 February 2017.
  5. ^ a b "Pale Moon - Technical Details".
  6. ^ "Pale Moon language packs". Moonchild Productions. Retrieved 2 March 2021.
  7. ^ a b "Pale Moon redistribution", Official website, retrieved 10 February 2017
  8. ^ a b "The Pale Moon Project homepage". Pale Moon. Retrieved 9 January 2017.
  9. ^ a b c "Pale Moon future roadmap". Pale Moon. Retrieved 9 February 2017.
  10. ^ Needham, Kev (21 August 2015). "The Future of Developing Firefox Add-ons". Mozilla Add-ons Blog. Archived from the original on 5 September 2015. Retrieved 7 September 2015.
  11. ^ Villalobos, Jorge (16 February 2017). "The Road to Firefox 57 – Compatibility Milestones". Mozilla Add-ons Blog. Archived from the original on 17 February 2017. Retrieved 17 February 2017.
  12. ^ Straver (Moonchild), Mark (30 October 2019). "Re: Will Flash player be supported after 2020?". Pale Moon. Retrieved 18 July 2020.
  13. ^ "Pale Moon future roadmap". Pale Moon. Retrieved 18 July 2020. Pale Moon supports NPAPI plug-ins. Unlike Firefox, we will not be deprecating or removing support for these kinds of plug-ins. This means that you will be able to continue using your media, authentication, gaming, and other plug-ins in Pale Moon like Flash, Silverlight, bank-authenticators or networking plug-ins for specific purposes.
  14. ^ "Multiprocess Firefox". Mozilla. Retrieved 24 August 2018.
  15. ^ "Multi-process, or: the drawbacks nobody ever talks about". Pale Moon forum. M.C. Straver. Retrieved 24 August 2018.
  16. ^ "Pale Moon - Add-ons - Themes".
  17. ^ Robijn, Arjen (11 February 2015). "Browser Pale Moon Integrates New Personal Start Page" (Press release). Amsterdam: PRWeb.
  18. ^ "Pale Moon 24.3.0 released! - Pale Moon forum". Retrieved 9 April 2017.
  19. ^ "End of Windows XP support in Pale Moon". Archived from the original on 26 August 2017.
  20. ^ WinterClaws; Moonchild (M.C. Straver). "Pale Moon 27.9.4 for Snow Leopard". Pale Moon forum. Post 5 (#p146639) and 11 (#p151480). Retrieved 23 April 2020. It was a bit disheartening to hear that v28.x SL builds will no longer be made but still…" "…Pale Moon 28 does not run on Snow Leopard.
  21. ^ "Building Palemoon 27 for XP".
  22. ^ "UXP and allied Project Contributors.. Your rights are being violated along with the MPL. - Pale Moon forum". Retrieved 26 October 2021.
  23. ^ wicknix (6 April 2020). "Arctic Fox web browser for 10.6 (32 & 64-bit)". MacRumors Forums. Retrieved 23 April 2020.
  24. ^ "Pale Moon SSE for Linux".
  25. ^ "End-of-Life announcement for SSE-only Linux Pale Moon - Pale Moon forum". Retrieved 25 October 2021.
  26. ^ "Pale Moon branding information". Official website.
  27. ^ a b "History of the Pale Moon project". Moonchild Productions. Retrieved 6 February 2017.
  28. ^ "What is Pale Moon's versioning scheme like?".
  29. ^ "The Future of Pale Moon".
  30. ^ "Jetpack Style Extensions". Retrieved 10 February 2017.
  31. ^ Moonchild (5 September 2021). "Unstable channel discontinued". Pale Moon forum.
  32. ^ "UXP and allied Project Contributors.. Your rights are being violated along with the MPL. - Page 7". Pale Moon forums.
  33. ^ "UXP vs goanna".
  34. ^ Brinkmann, Martin (17 November 2017). "Pale Moon team releases first version of Basilisk browser". GHacks. Retrieved 20 November 2017.
  35. ^ M.C. Straver (20 April 2018). "Basilisk's nature (a small clarification)".
  36. ^ "Release Pale Moon 28.0.0 · MoonchildProductions/UXP". GitHub.
  37. ^ "Pale Moon for Android". Retrieved 9 February 2017.
  38. ^ "Pale Moon for Android 24.7.1". 3 August 2014.
  39. ^ "I may have to let Pale Moon for Android go. :(". 16 April 2015.
  40. ^ "Pale Moon for Android updated to 25.9.6!". Retrieved 9 February 2017.
  41. ^ "Moonchild" (M.C. Straver) (15 March 2017). "Current Mac development status". Pale Moon forum. Retrieved 24 April 2020.
  42. ^ "End of Macintosh support - Pale Moon forum". Retrieved 24 March 2021.
  43. ^ "White Star". Retrieved 9 August 2021. External link in |website= (help)
  44. ^ Nawrocki, Matt. "Review: Pale Moon web browser for Windows". TechRepublic. Retrieved 12 February 2017.
  45. ^ a b Brinkmann, Martin (3 January 2016). "32-bit vs 64-bit browsers: which version has the edge?". GHacks. Retrieved 12 February 2017.
  46. ^ "Moonchild" (M.C. Straver) (9 April 2012). "What's the deal with browser benchmarks?". Pale Moon forum. Retrieved 22 June 2017.
  47. ^ "Google deprecates Octane JavaScript benchmark, because everyone is basically cheating". Ars Technica. 13 April 2017. Retrieved 23 July 2019.
  48. ^ Meurer, Benedikt (16 December 2016). "The truth about traditional JavaScript benchmarks". Retrieved 23 July 2019.
  49. ^ "Retiring Octane". V8. 12 April 2017. Archived from the original on 12 April 2017. Retrieved 23 July 2019.
  50. ^ "Warp: Improved JS performance in Firefox 83". 14 November 2020. Retrieved 14 November 2020.
  51. ^ "Browser Market Share Worldwide – Mar 2019 - Mar 2020" (CSV). StatCounter. Retrieved 24 April 2020.
  52. ^ "Moonchild" (M.C. Straver) (10 July 2019). "Data breach post-mortem". Pale Moon forum. Retrieved 17 November 2019.