An open source userscript manager. The fork of Violentmonkey with performance speed.

Libertybear provides userscripts support for browsers. We upgrade some components related to script launch speed and fix some Violentmonkey bugs, maybe some of this content is derived from Violentmonkey's policy and we confirm this project is tweaked. edited from Violentmonkey's source code


  • Powerful
    • Automate your work.
    • Customize web pages.
  • Data on the cloud
    • Sync to cloud services.
    • Sync between different browsers.
  • User-friendly
    • Communicate with external editors.
    • Keep simple, no need to make choices.

Note: This extension does not contain any ads and does not modify web pages automatically. Any changes and modifications on the sites are done by installed scripts. Therefore, please install only scripts that you trust.

Supported Browsers

LibertyBear is built with web extension APIs, thus supports many browsers.
  • Chrome Chrome
  • Firefox Firefox
  • Edge Edge
  • Opera Opera
  • Vivaldi Vivaldi
  • Chromium Chromium


  • Violentmonkey Violentmonkey
  • Tampermonkey Tampermonkey
  • Greasemonkey Greasemonkey


You are absolutely welcome to contribute code to GitHub.

You are welcome to help with this website too. Documents, improvements, articles about Libertybear, etc.