Alternatives to Greasemonkey
A Firefox extension that runs user scripts to change how web pages look and behave. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Greasemonkey
A Firefox extension that runs user scripts to change how web pages look and behave.
Replacements
Listings that take over the same core job as Greasemonkey.
Tampermonkey
Userscript manager for running custom scripts on websites.
Tampermonkey runs the same scripts across every major browser rather than Firefox only, with backups and an editor, but it is closed source.
Violentmonkey
Open-source userscript manager with cloud backup.
Violentmonkey is open source under MIT, adds cloud backup of scripts through storage you own, and has slightly narrower compatibility than Tampermonkey for exotic scripts.
ScriptCat
A userscript manager extension compatible with Tampermonkey scripts that can also run background scripts.
ScriptCat is open source, runs Tampermonkey scripts and adds background scripts and extra APIs, though much of its script site community is Chinese-language.
Userscripts
An open-source userscript and userstyle manager for Safari on macOS and iOS.
Userscripts is an open-source manager for Safari on macOS and iOS that handles user styles too, and scripts from other managers may need adjustments.
Similar software
Related functionality, not a direct replacement.
