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Browser Extensions · head to head

Greasemonkey vs Night Eye

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
Night Eye logo

Night Eye

Browser Extensions

Dark mode on any website

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Greasemonkey firefox only. There is no Chrome, Edge or Safari build and there never has been.; Night Eye can impact browser performance, especially on older or less powerful devices due to color conversion processing
  • They diverge on capability: Greasemonkey covers Userscript execution, Night Eye covers Dark mode.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Greasemonkey and Night Eye actually diverge.

Attributes where Greasemonkey and Night Eye differ
AttributeGreasemonkeyNight Eye
Pricing modelopen-sourceUnknown
PlatformsFirefoxChrome, Safari, Edge, Firefox, Opera, Brave
FoundedUnknown2018

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Browser Extensions).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Greasemonkey

  • Userscript execution
  • Built-in script editor
  • GM. API
  • @resource support
  • Script localisation
  • Firefox for Android

Only in Night Eye

  • Dark mode
  • Color analysis
  • Image preservation
  • Per-site settings
  • Chrome support
  • Firefox support
  • Edge support
  • Safari support

What people use each for

The jobs each tool is most often brought in to do.

Greasemonkey

  • Restyling or de-cluttering a site you use dailynot Night Eye
  • Automating a repetitive action on a web applicationnot Night Eye
  • Adding a missing feature to a site you do not controlnot Night Eye
  • Running userscripts on Firefox for Androidnot Night Eye
  • Writing and testing your own scripts in the browsernot Night Eye

Night Eye

  • Force a consistent dark mode on websites that don't natively support onenot Greasemonkey
  • Reduce eye strain and blue light exposure during night browsing via a built-in blue-light filternot Greasemonkey
  • Per-site color, brightness, contrast, and saturation customizationnot Greasemonkey
  • Selectively convert only icons/small images rather than full images to preserve visual fidelity in dark modenot Greasemonkey

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Greasemonkey

  • Firefox only. There is no Chrome, Edge or Safari build and there never has been.
  • Its API diverged from the Tampermonkey conventions most shared scripts are written against, so a script from a sharing site may need adjusting to run.
  • The dashboard is plainer than Tampermonkey's, with no diff view when a script updates itself.
  • No cloud sync of the kind Tampermonkey and Violentmonkey offer; moving machines means exporting.
  • A userscript manager can read and rewrite every page you visit, so the security of the arrangement depends entirely on the scripts you choose to install.

Night Eye

  • Can impact browser performance, especially on older or less powerful devices due to color conversion processing
  • Ineffective on web applications with fixed color schemes that cannot be altered
  • Does not work offline or on non-web content
  • Limited customization on websites that have their own built-in dark mode implementation

Pricing, plan by plan

Greasemonkey

Free
  • Open sourceFree
    • Unlimited scripts
    • Built-in editor
    • No account required

Night Eye

Free
  • LiteFree
    • Dark mode on up to 5 websites
    • No ads
  • Pro$9/year
    • Up to 3 browsers
  • Pro Max$14/year
    • Up to 6 browsers
  • Lifetime$40/mo
    • Unlimited browsers
    • Lifetime updates

Which should you pick?

Choose Greasemonkey if

  • You need userscript execution.
  • You want to start without paying.
  • You work on Firefox.
  • You also want built-in script editor.
Greasemonkey review

Choose Night Eye if

  • You need dark mode.
  • You want to start without paying.
  • You work on Chrome, Safari, Edge, Firefox, Opera, Brave.
  • You also want color analysis.
Night Eye review

Questions people ask

Is Greasemonkey or Night Eye better?
Neither clearly leads. Greasemonkey starts at Free and Night Eye at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or Night Eye?
Greasemonkey starts at Free and Night Eye at Free.
Does Greasemonkey or Night Eye run on more platforms?
Greasemonkey runs on Firefox. Night Eye runs on Chrome, Safari, Edge, Firefox, Opera, Brave.
Can I use Greasemonkey for free?
Both have a free tier, so you can try either at no cost before committing.
What is Greasemonkey best used for?
Greasemonkey is most often used for restyling or de-cluttering a site you use daily, automating a repetitive action on a web application, adding a missing feature to a site you do not control, running userscripts on firefox for android. Of those, restyling or de-cluttering a site you use daily and automating a repetitive action on a web application are not what Night Eye is typically brought in for.
What can Greasemonkey do that Night Eye cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. Night Eye covers Dark mode, Color analysis, Image preservation, Per-site settings.

Answered from the vendors’ own pages

Greasemonkey: Is Greasemonkey still maintained?

Yes. Version 4.14 was released on 2 June 2026, and the project has an active repository, bug tracker and discussion groups.

Source
Night Eye: What is Night Eye?

Night Eye is a browser extension that applies dark mode to websites by analyzing page colors and converting them into a comfortable dark theme. It preserves photos and videos and offers customization options for brightness, contrast, and blue light filtering.

Source
Greasemonkey: Does Greasemonkey work on Chrome?

No. It is a Firefox extension and has never shipped for Chrome. Violentmonkey and Tampermonkey are the equivalents there.

Source
Night Eye: What is the pricing for Night Eye?

Night Eye Lite is free with dark mode on up to 5 websites. Night Eye Pro costs $9/year for up to 3 browsers, Night Eye Pro Max costs $14/year for up to 6 browsers, and lifetime updates cost $40 for unlimited use across 10 browsers.

Source
Greasemonkey: Will Tampermonkey scripts run in Greasemonkey?

Often, but not always. Greasemonkey's API diverged from the conventions most shared scripts are written against, so a script may need its header or its GM calls adjusted.

Source
Night Eye: Which browsers does Night Eye support?

Night Eye is available for Chrome, Safari, Microsoft Edge, Firefox, Opera, Brave, and other Chromium-based browsers.

Source
Greasemonkey: Does Greasemonkey run on mobile?

On Firefox for Android, from version 4.12. There is no iOS build, because Firefox on iOS cannot load extensions of this kind.

Source
Night Eye: Does Night Eye track my browsing?

No. Night Eye does not monitor, process, or store browsing activity. Webpage conversion is performed locally on the user's device. No ads appear in the free Lite version.

Source
Greasemonkey: What is the GM API?

The set of functions a userscript manager exposes to scripts, named after Greasemonkey, which defined it. Greasemonkey supports the promise-based GM. form including GM.xmlHttpRequest and GM.registerMenuCommand.

Source
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