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Browser Extensions · head to head

FireMonkey vs Mozilla Firefox

FireMonkey logo

FireMonkey

Browser Extensions

User scripts and user styles in one Firefox extension

From
Free
Rated
-
Full reviewWebsite
Mozilla Firefox logo

Mozilla Firefox

Technology

An independent web browser with its own rendering engine, funded almost entirely by search placement deals.

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: FireMonkey firefox only, and requires a recent one: version 93 on desktop, 113 on Android.; Mozilla Firefox roughly 85 per cent of Mozilla's revenue comes from search default placement deals, overwhelmingly with Google, so the organisation that competes with Chrome depends on Chrome's owner for its funding and any renegotiation lands on Firefox's engineering budget within a quarter.
  • They diverge on capability: FireMonkey covers Scripts and styles together, Mozilla Firefox covers Gecko engine.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which FireMonkey and Mozilla Firefox actually diverge.

Attributes where FireMonkey and Mozilla Firefox differ
AttributeFireMonkeyMozilla Firefox
Pricing modelopen-sourceUnknown
PlatformsFirefoxWindows, macOS, Linux, iOS, Android
CategoryBrowser ExtensionsTechnology
FoundedUnknown2004

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

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 FireMonkey

  • Scripts and styles together
  • Monaco editor with ESLint
  • Unlimited client-side storage
  • Global injection
  • Notifications and clipboard
  • Firefox for Android

Only in Mozilla Firefox

  • Gecko engine
  • Full webRequest blocking
  • Total Cookie Protection
  • Container tabs
  • Extended Support Release
  • policies.json and ADMX
  • Built-in developer tools
  • Firefox Sync

What people use each for

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

FireMonkey

  • Running user scripts and user styles without two separate extensionsnot Mozilla Firefox
  • Restyling sites with CSS alongside scripted behaviour changesnot Mozilla Firefox
  • Editing scripts in a full editor inside the browsernot Mozilla Firefox
  • Injecting CSS globally across every sitenot Mozilla Firefox
  • Managing a mixed library of scripts and styles from one dashboardnot Mozilla Firefox

Mozilla Firefox

  • Web development where you need to test against a non-Chromium engine before shipping, because Chromium-only testing hides real bugsnot FireMonkey
  • Users who require a full-strength content blocker, which Chrome's Manifest V3 no longer permitsnot FireMonkey
  • Managed fleets that need a browser on a slow release cadence with Group Policy control, using the ESR channelnot FireMonkey
  • Handling several accounts on the same service at once through container tabs, without separate profiles or private windowsnot FireMonkey

Where each one falls short

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

FireMonkey

  • Firefox only, and requires a recent one: version 93 on desktop, 113 on Android.
  • Not a drop-in replacement for Greasemonkey, Tampermonkey or Stylus. The project says so itself, so an existing library may need adjusting.
  • A much smaller user base than Tampermonkey or Violentmonkey, which means fewer people have hit the bug you are about to hit.
  • No Chrome, Edge or Safari build, so it cannot be the answer for anyone working across browsers.
  • Combining scripts and styles in one extension also combines the blast radius: one extension with permission to inject both into every page.

Mozilla Firefox

  • Roughly 85 per cent of Mozilla's revenue comes from search default placement deals, overwhelmingly with Google, so the organisation that competes with Chrome depends on Chrome's owner for its funding and any renegotiation lands on Firefox's engineering budget within a quarter.
  • Desktop market share sits at a few per cent, so commercial sites are tested against Chrome and Safari and a Firefox-only rendering or WebRTC bug is triaged as low priority by the site owner, leaving you with the workaround.
  • On iOS and iPadOS the browser is a WebKit shell required by Apple's rules, so it delivers the interface and Sync but none of the engine, extension or tracking-protection behaviour that make Firefox worth choosing on desktop.
  • Mozilla declines to implement several hardware-facing APIs on principle, including WebUSB, WebSerial, Web Bluetooth and WebHID, so a web application that talks to a device simply does not run and no configuration flag changes that.
  • Enterprise management is limited to policies.json and ADMX templates; there is no first-party equivalent of Chrome Browser Cloud Management, so fleet-wide reporting on versions and extensions requires third-party tooling you have to buy or build.
  • Mozilla repeatedly ships decisions its own user base objects to, such as enabling Privacy Preserving Attribution by default and the 2025 Terms of Use rewrite, and reversals arrive after the news cycle, so deploying it on a privacy argument means owning the communications work each time.

Pricing, plan by plan

FireMonkey

Free
  • Open sourceFree
    • MPL-2.0 licensed
    • Unlimited scripts and styles
    • No account required

Mozilla Firefox

Free

No published plan breakdown. See the Mozilla Firefox review.

Which should you pick?

Choose FireMonkey if

  • You need scripts and styles together.
  • You want to start without paying.
  • You work on Firefox.
  • You also want monaco editor with eslint.
FireMonkey review

Choose Mozilla Firefox if

  • You need gecko engine.
  • You want to start without paying.
  • You work on Windows, macOS, Linux, iOS, Android.
  • You also want full webrequest blocking.
Mozilla Firefox review

Questions people ask

Is FireMonkey or Mozilla Firefox better?
Neither clearly leads. FireMonkey starts at Free and Mozilla Firefox at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, FireMonkey or Mozilla Firefox?
FireMonkey starts at Free and Mozilla Firefox at Free.
Does FireMonkey or Mozilla Firefox run on more platforms?
FireMonkey runs on Firefox. Mozilla Firefox runs on Windows, macOS, Linux, iOS, Android.
Can I use FireMonkey for free?
Both have a free tier, so you can try either at no cost before committing.
What is FireMonkey best used for?
FireMonkey is most often used for running user scripts and user styles without two separate extensions, restyling sites with css alongside scripted behaviour changes, editing scripts in a full editor inside the browser, injecting css globally across every site. Of those, running user scripts and user styles without two separate extensions and restyling sites with css alongside scripted behaviour changes are not what Mozilla Firefox is typically brought in for.
What can FireMonkey do that Mozilla Firefox cannot?
FireMonkey covers Scripts and styles together, Monaco editor with ESLint, Unlimited client-side storage, Global injection. Mozilla Firefox covers Gecko engine, Full webRequest blocking, Total Cookie Protection, Container tabs.

Answered from the vendors’ own pages

FireMonkey: What makes FireMonkey different from Violentmonkey?

It manages user styles as well as user scripts. The usual arrangement is a script manager plus a separate style manager such as Stylus; FireMonkey replaces both with one extension.

Source
Mozilla Firefox: Does uBlock Origin still work on Firefox?

Yes. Firefox has kept the blocking webRequest API that Chrome removed with Manifest V3, so uBlock Origin runs with its full rule set rather than the cut-down Lite version Chrome requires.

FireMonkey: Which browsers does FireMonkey support?

Firefox only. Desktop requires Firefox 93 or later and Android requires 113, with an API minimum of 102.

Source
Mozilla Firefox: Is Firefox on iPhone the same browser?

No. Apple's platform rules require it to use WebKit, so on iOS and iPadOS you get Firefox's interface, Sync and bookmarks on top of Safari's engine. The privacy and extension behaviour are not the same.

FireMonkey: Is FireMonkey open source?

Yes, under the MPL-2.0 licence.

Source
Mozilla Firefox: How is Mozilla funded, and does that matter?

Mainly by payments for making a search engine the default, with Google as the dominant payer. It matters because it is a single-source dependency on a direct competitor, and it has been the subject of antitrust litigation whose outcome Mozilla does not control.

FireMonkey: Will my existing Tampermonkey scripts work?

Not necessarily. The project states that while it shares functionality with Greasemonkey, Tampermonkey and Stylus, there are differences, so scripts and styles written for those may need adjusting.

Source
Mozilla Firefox: Can I manage it across a company fleet?

Yes, through policies.json or Windows Group Policy with the ADMX templates, and the ESR channel gives you a roughly yearly major version instead of four-weekly. There is no first-party cloud management console, so reporting needs other tooling.

FireMonkey: What editor does FireMonkey use?

Current versions use the Monaco editor with ESLint, the same editor component that powers VS Code.

Source
Mozilla Firefox: Will every site work in it?

Most will. The exceptions cluster around sites tested only in Chrome, legacy enterprise applications, and anything using WebUSB, WebSerial, Web Bluetooth or WebHID, which Firefox does not implement at all.

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