Key features
- userscript installation from repositories like Greasy Fork
- built-in script editor with syntax highlighting
- per-site enable and disable controls
- scheduled and automatic script updates
- cross-browser userscript compatibility
What Tampermonkey does
Tampermonkey is a userscript manager: it lets you install small scripts that modify how specific web pages look or behave, such as hiding elements, adding buttons, or automating a form. Scripts come from repositories like Greasy Fork or from your own code, and Tampermonkey's dashboard controls which ones run and where.
Is Tampermonkey safe?
Tampermonkey itself is open source, but the safety of any individual userscript depends on what that script does, since scripts can read and modify page content on sites you grant them access to. Install scripts only from sources you trust, and review a script's code or reputation before adding it.
Tampermonkey vs built-in browser features
Unlike single-purpose extensions, Tampermonkey doesn't do anything on its own beyond hosting scripts you add. That makes it flexible for advanced users who want a specific site tweak that no dedicated extension offers, but it requires some setup compared to installing a ready-made tool.