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Browser Extensions · head to head

Greasemonkey vs Tampermonkey

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
Tampermonkey logo

Tampermonkey

Browser Extensions

The most popular userscript manager

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.; Tampermonkey only source code up to version 2.9 is GPLv3; all newer versions are distributed under a proprietary license despite the extension itself being free to use
  • They diverge on capability: Greasemonkey covers Userscript execution, Tampermonkey covers Userscript management.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Greasemonkey and Tampermonkey actually diverge.

Attributes where Greasemonkey and Tampermonkey differ
AttributeGreasemonkeyTampermonkey
PlatformsFirefoxWeb, Windows, macOS, Linux, Android
FoundedUnknown2010

Identical on both: starting price (Free), pricing model (open-source), 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 Tampermonkey

  • Userscript management
  • Script editor
  • Auto-update
  • Cloud sync
  • 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 Tampermonkey
  • Automating a repetitive action on a web applicationnot Tampermonkey
  • Adding a missing feature to a site you do not controlnot Tampermonkey
  • Running userscripts on Firefox for Androidnot Tampermonkey
  • Writing and testing your own scripts in the browsernot Tampermonkey

Tampermonkey

  • Auto-run custom JavaScript to add features to specific websitesnot Greasemonkey
  • Block ads, remove clutter, or reformat page layout via community/personal userscriptsnot Greasemonkey
  • Run scripts sourced from Greasy Fork or similar userscript repositoriesnot Greasemonkey
  • Automate repetitive web tasks such as form-filling or redirect skipping via installed scriptsnot 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.

Tampermonkey

  • Only source code up to version 2.9 is GPLv3; all newer versions are distributed under a proprietary license despite the extension itself being free to use
  • Under Manifest V3, GM_webRequest is not (yet) supported
  • Under Manifest V3, GM_xmlhttpRequest fires only one progress event instead of streaming progress, requiring a responseType: 'stream' workaround
  • Since v5.3.2, Chrome/Edge (MV3) requires the user to manually enable Developer Mode, or from Chrome 138+ a per-extension 'Allow User Scripts' toggle, before any userscript will run

Pricing, plan by plan

Greasemonkey

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

Tampermonkey

Free

No published plan breakdown. See the Tampermonkey review.

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 Tampermonkey if

  • You need userscript management.
  • You want to start without paying.
  • You work on Web, Windows, macOS, Linux, Android.
  • You also want script editor.
Tampermonkey review

Questions people ask

Is Greasemonkey or Tampermonkey better?
Neither clearly leads. Greasemonkey starts at Free and Tampermonkey at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or Tampermonkey?
Greasemonkey starts at Free and Tampermonkey at Free.
Does Greasemonkey or Tampermonkey run on more platforms?
Greasemonkey runs on Firefox. Tampermonkey runs on Web, Windows, macOS, Linux, Android.
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 Tampermonkey is typically brought in for.
What can Greasemonkey do that Tampermonkey cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. Tampermonkey covers Userscript management, Script editor, Auto-update, Cloud sync.

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
Tampermonkey: How much does Tampermonkey cost?

Tampermonkey is completely free for all versions and across all supported browsers including Chrome, Edge, Safari, Opera, and Firefox.

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
Tampermonkey: Is Tampermonkey available on all browsers?

Yes, Tampermonkey is available on Chrome 120 and later, Microsoft Edge, Safari, Opera Next, and Firefox with no cost.

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
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
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