Is It Safe to Use Violentmonkey with Userscripts?

Updated

Violentmonkey itself is an open source userscript manager that, according to its official site, "does not contain any ads and does not modify web pages automatically." That means the extension by itself is not what changes a page — any change comes from the userscripts you choose to install. So the practical answer is: the extension is designed to stay out of the way, but the safety of your setup depends mainly on which scripts you install and trust. The site's own guidance is direct: "please install only scripts that you trust."

What Violentmonkey does and does not do

The distinction matters for judging risk:

  • It does not modify pages on its own. The site states the extension "does not modify web pages automatically." Without scripts, it does not rewrite or inject content into sites.
  • It does not contain ads. No ad injection is built in.
  • It runs the scripts you add. "Any changes and modifications on the sites are done by installed scripts." The extension is the execution environment; the scripts are the instructions.
  • It is open source. Code is available on GitHub, so the extension's behavior can be inspected rather than taken on faith.

This split is the core of the safety question. Installing Violentmonkey is not the same as trusting every script in a userscript repository.

Where the real risk sits: the scripts

A userscript can read and change page content, and depending on how it is written and how your manager grants permissions, it may reach further. The extension's own note frames the user's responsibility clearly: because changes come from installed scripts, "please install only scripts that you trust."

Before installing a script, check:

  • Source and author. Is the script hosted somewhere with a visible author, version history, and issue tracker?
  • What it requests. Does a small cosmetic tweak ask for broad access across all sites?
  • Readability. Can you skim the code, or is it obfuscated/minified with no source?
  • Reviews and recency. Has it been updated recently, and do other users report problems?
  • Necessity. Do you actually need this script, or does a built-in browser feature cover it?

If a script fails these checks, the safe move is not to install it — the extension cannot make an untrusted script trustworthy.

Browser and installation context

Violentmonkey is built with web extension APIs and supports many browsers. The site lists installation via the Chrome Web Store, Firefox AMO, Microsoft Edge Addons, and GitHub Releases, with all versions (including Beta and MV2) available on the releases page.

One current detail worth knowing: the site notes that "Violentmonkey in Chrome Web Store has been updated to ManifestV3." If you are comparing install sources or troubleshooting behavior differences, that is a relevant fact about the Chrome Web Store build.

Practical safety checklist

  1. Install the extension from an official listing (Chrome Web Store, Firefox AMO, Edge Addons) or the project's GitHub Releases.
  2. Treat each userscript as a separate trust decision — the extension's safety does not extend to scripts automatically.
  3. Prefer scripts with visible source, an identifiable author, and recent activity.
  4. Review what a script can access before enabling it, and remove scripts you no longer use.
  5. Remember the site's own rule: install only scripts you trust.

Bottom line

Violentmonkey is an open source manager that does not inject ads or alter pages by itself; the modifications you see come entirely from installed scripts. That makes the extension a relatively neutral tool, but it also means your safety depends on script selection. If you stick to trusted, inspectable scripts from reputable sources, the setup is reasonable; if you install unknown scripts with broad permissions, the extension offers no protection against them.