Softwr

Browser Extensions · head to head

Greasemonkey vs Stylus

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
Stylus logo

Stylus

Browser Extensions

Restyle the web with custom CSS

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.; Stylus crashes and instability when applying certain styles
  • They diverge on capability: Greasemonkey covers Userscript execution, Stylus covers Custom CSS injection.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Greasemonkey and Stylus actually diverge.

Attributes where Greasemonkey and Stylus differ
AttributeGreasemonkeyStylus
Pricing modelopen-sourcefree
PlatformsFirefoxChrome, Firefox, Edge, Opera
FoundedUnknown2017

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 Stylus

  • Custom CSS injection
  • Style management
  • userstyles.world integration
  • Built-in editor
  • Chrome support
  • Firefox support
  • Edge support
  • Opera 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 Stylus
  • Automating a repetitive action on a web applicationnot Stylus
  • Adding a missing feature to a site you do not controlnot Stylus
  • Running userscripts on Firefox for Androidnot Stylus
  • Writing and testing your own scripts in the browsernot Stylus

Stylus

  • Customizing website appearance with community-created CSS themesnot Greasemonkey
  • Writing personal style overrides for specific websitesnot Greasemonkey
  • Managing multiple styles across different websites automaticallynot Greasemonkey
  • Searching and installing user-styles for current websitesnot Greasemonkey
  • Migrating style collections from Stylish extensionnot 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.

Stylus

  • Crashes and instability when applying certain styles
  • No visual element selector tool for identifying page elements to style
  • Security risk if downloading and applying untrusted user-created styles

Pricing, plan by plan

Greasemonkey

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

Stylus

Free
  • FreeFree
    • Custom CSS
    • Style library
    • Style editor

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 Stylus if

  • You need custom css injection.
  • You want to start without paying.
  • You work on Chrome, Firefox, Edge, Opera.
  • You also want style management.
Stylus review

Questions people ask

Is Greasemonkey or Stylus better?
Neither clearly leads. Greasemonkey starts at Free and Stylus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or Stylus?
Greasemonkey starts at Free and Stylus at Free.
Does Greasemonkey or Stylus run on more platforms?
Greasemonkey runs on Firefox. Stylus runs on Chrome, Firefox, Edge, Opera.
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 Stylus is typically brought in for.
What can Greasemonkey do that Stylus cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. Stylus covers Custom CSS injection, Style management, userstyles.world integration, Built-in editor.

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
Stylus: Is Stylus free?

Yes. Stylus is completely free and open-source, available for Chrome, Firefox, Edge, and Opera browsers.

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
Stylus: Can I use Stylus to change the browser UI?

No. Due to WebExtensions security restrictions, Stylus can only customize website pages, not the browser interface itself.

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
Stylus: What CSS pre-processors does Stylus support?

Stylus supports CSS, LESS, and Stylus syntax with built-in linting using Stylelint and CSSLint-mod with customizable rules.

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
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
Share

Related pages

More on Greasemonkey

More on Stylus

Keep looking

Other head to heads