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Browser Extensions · head to head

Capital One Shopping vs Greasemonkey

Capital One Shopping logo

Capital One Shopping

Browser Extensions

Automatically save while you shop

From
Free
Rated
-
Full reviewWebsite
Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Capital One Shopping limited to coupon and price comparison features, no true cashback rewards; Greasemonkey firefox only. There is no Chrome, Edge or Safari build and there never has been.
  • They diverge on capability: Capital One Shopping covers Price comparison, Greasemonkey covers Userscript execution.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Capital One Shopping and Greasemonkey actually diverge.

Attributes where Capital One Shopping and Greasemonkey differ
AttributeCapital One ShoppingGreasemonkey
Pricing modelUnknownopen-source
PlatformsWeb, iOS, AndroidFirefox
Founded2014Unknown

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 Capital One Shopping

  • Price comparison
  • Coupon finder
  • Price tracking
  • Credits rewards
  • Chrome support
  • Firefox support
  • Edge support
  • Safari support

Only in Greasemonkey

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

What people use each for

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

Capital One Shopping

  • Automatically applying coupon codes at checkoutnot Greasemonkey
  • Tracking price drops on itemsnot Greasemonkey
  • Earning category-based cashback on purchasesnot Greasemonkey

Greasemonkey

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

Where each one falls short

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

Capital One Shopping

  • Limited to coupon and price comparison features, no true cashback rewards
  • Dependent on retailers offering coupons or price matching
  • Browser extension adds processing overhead to shopping sessions

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.

Pricing, plan by plan

Capital One Shopping

Free

No published plan breakdown. See the Capital One Shopping review.

Greasemonkey

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

Which should you pick?

Choose Capital One Shopping if

  • You need price comparison.
  • You want to start without paying.
  • You work on Web, iOS, Android.
  • You also want coupon finder.
Capital One Shopping review

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

Questions people ask

Is Capital One Shopping or Greasemonkey better?
Neither clearly leads. Capital One Shopping starts at Free and Greasemonkey at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Capital One Shopping or Greasemonkey?
Capital One Shopping starts at Free and Greasemonkey at Free.
Does Capital One Shopping or Greasemonkey run on more platforms?
Capital One Shopping runs on Web, iOS, Android. Greasemonkey runs on Firefox.
Can I use Capital One Shopping for free?
Both have a free tier, so you can try either at no cost before committing.
What is Capital One Shopping best used for?
Capital One Shopping is most often used for automatically applying coupon codes at checkout, tracking price drops on items, earning category-based cashback on purchases. Of those, automatically applying coupon codes at checkout and tracking price drops on items are not what Greasemonkey is typically brought in for.
What can Capital One Shopping do that Greasemonkey cannot?
Capital One Shopping covers Price comparison, Coupon finder, Price tracking, Credits rewards. Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support.

Answered from the vendors’ own pages

Capital One Shopping: Is Capital One Shopping free?

Yes. Capital One Shopping is 100% free to install and use on desktop or mobile. There are no fees or charges.

Source
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
Capital One Shopping: Does Capital One Shopping require a Capital One account?

No. Capital One Shopping is free for everyone, including people who are not Capital One customers.

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
Capital One Shopping: What platforms does Capital One Shopping support?

Capital One Shopping is available as a browser extension for desktop browsers and as a mobile app for iOS and Android.

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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