First released in June 2014 as a Chrome and Opera extension, by winter 2015, the extension had expanded to other browsers. uBlock was developed by Raymond Hill to use community-maintained block lists, while adding features and raising the code quality to release standards. Development started by forking from the codebase of HTTP Switchboard along with another blocking extension called uMatrix, designed for advanced users.

UBlock was initially named 'μBlock' but the name was later changed to 'uBlock' to avoid confusion as to how the Greek letter μ (Mu/Micro) in 'μBlock' should be pronounced.

UBlock Origin is actively developed and maintained by its creator and lead developer Raymond Hill. uBlock Origin's stated purpose is to give users the means to enforce their own (content-filtering) choices. uBlock Origin has received praise from technology websites and is reported to be much less memory-intensive than other extensions with similar functionality. The extension is available for Chrome, Chromium, Edge, Firefox, Opera, Pale Moon, as well as versions of Safari prior to 13.

UBlock Origin ( / ˈ j uː b l ɒ k/ ' YOO-block' ) is a free and open-source browser extension for content filtering, including ad blocking.

Ublock origin mobile firefox