FireMonkeyvs
Violentmonkey
Violentmonkey: Open source script manager for Firefox with a much larger user base and wider script compatibility, but it does not manage user styles.
FireMonkey
User scripts and user styles in one Firefox extension
As of 15 September 2026, FireMonkey is free to use. Firefox extension that manages user scripts and user styles together, rather than needing one tool for JavaScript and another for CSS. Softwr lists it under Browser Extensions. FireMonkey is available on Browser extension.
Overview
What FireMonkey does
FireMonkey is a Firefox extension that manages user scripts and user styles in the same place. That is the whole proposition, and for a certain kind of user it is the only one that matters: the conventional arrangement is a script manager such as Greasemonkey or Violentmonkey alongside a separate style manager such as Stylus, which means two extensions, two dashboards, two backup routines and two sets of matching rules to keep straight. Underneath, it does what the category does. It injects JavaScript and CSS into pages matching rules you set, across all sites if you want, with unlimited client-side storage available to scripts and support for notifications and clipboard access. Recent versions ship the Monaco editor with ESLint, so the in-browser editing experience is closer to a real code editor than to a text box. It is Firefox only, requiring version 93 or later on desktop and 113 on Android, and it is released under the MPL-2.0 licence. The project is explicit that while it overlaps with Greasemonkey, Tampermonkey and Stylus, it is not a drop-in replacement for any of them, so scripts and styles written for those may need attention.
What people use it 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
- Managing a mixed library of scripts and styles from one dashboard
The honest half
Where it falls short
Concrete and checkable, so you can decide whether any of them matter to you. This is the half of a review a vendor will not write about 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.
Cross-shopped
What people choose instead of FireMonkey
Each pairing was judged by two reviewers asking whether a buyer would genuinely weigh the two against each other. The ones that failed were deleted rather than published.
- FireMonkeyvsGreasemonkey
Greasemonkey: The original Firefox script manager, longer established and simpler, again without style management.
- FireMonkeyvsTampermonkey
Tampermonkey: The most widely targeted manager with the fullest dashboard, closed source, and scripts only.
Pricing
What FireMonkey costs
Taken from the vendor's own pricing page. Prices move, so check before you buy.
Open source
Free
- MPL-2.0 licensed
- Unlimited scripts and styles
- No account required
Capabilities
Features
Scripts and styles together
Manages user scripts and user styles in one extension, replacing the usual pairing of a script manager and a separate style manager.
Monaco editor with ESLint
Current versions edit in Monaco, the editor behind VS Code, with linting as you type.
Unlimited client-side storage
Scripts can store data locally without the quota limits some managers impose.
Global injection
Inject scripts or CSS across all sites, or narrow to matching rules per item.
Notifications and clipboard
Scripts can raise notifications and read or write the clipboard through the extension's API.
Firefox for Android
Supported on Android from Firefox 113, with an API minimum of 102.
Answered, with sources
Questions people ask
Each answer names the page it came from, so you can check it rather than take our word for it.
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.
SourceWhich browsers does FireMonkey support?
Firefox only. Desktop requires Firefox 93 or later and Android requires 113, with an API minimum of 102.
SourceIs FireMonkey open source?
Yes, under the MPL-2.0 licence.
SourceWill 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.
SourceWhat editor does FireMonkey use?
Current versions use the Monaco editor with ESLint, the same editor component that powers VS Code.
SourceKeep looking
Where to go from FireMonkey
- FireMonkey alternativesEvery product people weigh against it
- FireMonkey pricingPlans, floors and what the tiers exclude
- FireMonkey badgesWhich rules it meets, and the figure behind each
- All Browser Extensions softwareThe full category
- Best Browser Extensions softwareThe shortlist, and how it was cut
Best Browser Extensions software for
Compare FireMonkey with
- Greasemonkey
- Violentmonkey
- Tampermonkey
- Userscripts
- Stay
- GoFullPage
- Stylus
- Dark Reader
- Raindrop.io
- Privacy Badger
- AdBlock Plus
- Night Eye
- React Developer Tools
- Save to Google Drive
- Vimeo Record
- Vue.js Devtools
- Userscripts
Other Browser Extensions software
Safari userscript manager that runs Tampermonkey scripts
Free, then $5/one-time12 researched notes
Softwr does not host reviews and shows no star rating for FireMonkey, because a rating we did not collect is not ours to publish. What is here is the pricing and platform detail from the vendor’s own pages, limitations we could state concretely, and alternatives a reviewer confirmed people weigh against it. Tell us if any of it is wrong.
More on FireMonkey
FireMonkey alternatives
What people switch to, and what they give up
FireMonkey pricing
Every tier, and where the cost actually lands
Compare FireMonkey
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