Serious Discussion UltimaDark - The Fastest Dark Mode Extension for Firefox

[rashmi]

I'm trying Firefox and wanted a dark mode extension. Tried several options, including Dark Reader, and encountered problems with each. I've been using UltimaDark, and while it has some flaws, I enjoy it, and it doesn't affect website speed. If you need dark mode in Firefox, I suggest trying UltimaDark. Have you used it? Share your experience.

GitHub - ThomazPom/Moz-Ext-UltimaDark: A web extension that uses aggressive techniques to enable dark mode on every site.

A web extension that uses aggressive techniques to enable dark mode on every site. - ThomazPom/Moz-Ext-UltimaDark

github.com

 

[rashmi]

Although I liked UltimaDark, I removed it. DeepSeek reports that UltimaDark shows no signs of malicious or suspicious activity. I'll track its progress and whether the developer applies for the "recommended" badge. I'm using Dark Reader right now.

I couldn't find a suitable CSS dark mode solution for websites after several hours of testing with DeepSeek.

 

[rashmi]

Version 1.6.14
Released Aug 8, 2025

UltimaDark - The Fastest Dark Mode Extension version history - 25 versions – Add-ons for Firefox (en-US)

addons.mozilla.org

 

[rashmi]

Works well! Some screens!