The best open source alternative to Dark Reader is Midnight Lizard. If that doesn't suit you, our users have ranked more than 10 alternatives to Dark Reader and seven of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Dark Reader are Dark Background and Light Text, Dark Night Mode, Owl and Nightshift Dark Mode.
Midnight Lizard web-extension for Google Chrome™ and Mozilla Firefox™ provides custom color schemes for all websites.
Makes every page (or only pages that you want) to have light text on dark background. Exact colors are customizable.
It is a universal night mode for the entire Internet. It uses a special algorithm to automatically change the colors of the websites you visit into dark mode so that you can browse without straining your eyes, especially at night.
Owl transforms webpages with a comfortable dark theme on-the-fly, protecting your eyes from the glaring color schemes on most websites. Owl comes bundled with a ton of features. With Owl, you can:
Dark mode for Safari.
You can enable or disable dark mode on a per site basis.
This extension utilizes the CSS filter property. It inverts the whole page, then invertes back images and videos. Due to the double invert, some colors may be inaccurate.
This app helps to activate night theme on devices that don't provide this option in the system settings.
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Similar extension size as Dark Reader, but offers much more customization levels. It allows you to fine tune things like background image saturation and size.
If you want something smaller, you can just use an inversion extension, or even just change a setting on many browsers to invert.