# Greasemonkey

> Customize the way a web page displays or behaves, by using small bits of JavaScript.

Canonical page: [https://chrome-stats.com/d/greasemonkey](https://chrome-stats.com/d/greasemonkey)

## Overview

- **ID:** `greasemonkey`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Anthony Lieuallen
- **Category:** other
- **Daily users:** 158,523
- **Weekly downloads:** 1,941
- **Rating:** 4.19 / 5 (1,292 ratings)
- **Version:** 4.14
- **Last updated:** 2026-06-08
- **First published:** 2005-05-20
- **Size:** 593 KB
- **Data as of:** 2026-09-13
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/greasemonkey/)
- **Website:** [http://greasespot.net/](http://greasespot.net/)

## Description

**Greasemonkey** is a powerful Chrome extension that enables users to customize the appearance and behavior of web pages through small JavaScript scripts. Whether you want to modify layouts, add new functionalities, or automate repetitive tasks, Greasemonkey provides a flexible platform to personalize your browsing experience.

Users can create their own scripts or utilize a vast collection of existing ones available on the Greasemonkey wiki. This extension empowers you to enhance your favorite websites to better suit your needs without requiring advanced development skills. For support and tutorials, the Greasemonkey manual and script hosting resources are a great starting point.

## Rankings

- #117 — Overall
- #23 — Other extensions
- #13 — money
- #33 — base
- #38 — keyword
- #40 — javascript

## Permissions and access

### Permissions

- `<all_urls>`
- `clipboardWrite`
- `cookies`
- `downloads`
- `notifications`
- `storage`
- `tabs`
- `unlimitedStorage`
- `webNavigation`
- `webRequest`
- `webRequestBlocking`

## Safety

- **Risk impact:** Very high risk impact
- **Risk likelihood:** Low risk likelihood

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- This extension was updated more than 6 months ago. Older versions are more likely to be stable and safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

## Review summary

User reviews for the Greasemonkey Firefox add-on are mixed; some users appreciate that the extension works instantly and as intended, praising the developers' efforts. However, others report that it does not work for them, considering it a waste of time.

### Pros

- Extension works immediately as expected.
- Good work by the developers.

### Cons

- Not working for some users.

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Source: [Chrome-Stats](https://chrome-stats.com/d/greasemonkey)