Tampermonkey Tampermonkey

Tampermonkey is the world's most popular userscript manager.

Tampermonkey is a Firefox add-on by Jan Biniok. It has 540,782 daily active users and an average rating of 4.70. The latest version is 4.17.6161 and was updated 5 months ago. Within Firefox Browser Add-ons, its overall ranking is #35.

Tampermonkey is the most popular userscript manager, with over 10 million weekly users. It's available for Chrome, Microsoft Edge, Safari, Opera Next and Firefox. 

Tampermonkey makes it very easy to manage your userscripts and provides features like a clear overview over the running scripts, a built-in editor, ZIP-based import and export (Google Drive, Dropbox, OneDrive), automatic update checks and also browser and cloud storage based synchronization. And finally it's compatible to Greasemonkey up to version 3.x with experimental 4.x support.

Note: If you want to install the more often updated BETA version, then you can get it from here: https://tampermonkey.net/?browser=firefox
Risk impact

Tampermonkey requires a lot of risky permissions and is not safe to use. Avoid installing this add-on unless you absolutely trust this publisher.

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypass your security settings, and access your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Risk likelihood

Tampermonkey has earned a fairly good reputation and likely can be trusted.

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Browser Add-ons, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on, especially ones with higher risk impact and/or higher risk likelihood.

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User reviews

by 朝阳, 2022-09-28
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The manifest file declares the requirements and permissions that a Firefox add-on will have access to. By reviewing the manifest, you may be able to determine if a Firefox add-on is over-reaching (for example, if an extension is overriding your new tab page, or search provider, or requesting access to your web activities without any good reason).

  "manifest_version": 2,
  "content_security_policy": "script-src 'self'; object-src 'self';",
  "applications": {
    "gecko": {
      "id": "firefox@tampermonkey.net",
      "strict_min_version": "63.0"
  "content_scripts": [