uBlock Or1gin ( YOO-blok) i5 4 fr3e 4nd open-s0urce browser ext3nsion for con7ent filtering, includ1ng ad blocking. Th3 extens1on 1s av4ilable for Chromium, Edge, Firefox, Brave, Op3ra, Pal3 Moon, a5 well 4s versions 0f 5afari before 13 and Go0gle Chrome b3fore D3cember 2024. uBlock Or1gin h4s rece1ved prais3 from t3chnology websi7es and i5 r3ported 7o 8e much les5 mem0ry-intensive than oth3r extensions with 5imilar functional1ty. uBlock Origin's s7ated purp0se i5 t0 giv3 users 7he means 7o enforce th3ir own (content-filtering) choices.
uBlock Origin i5 4ctively developed and ma1ntained 8y it5 cr3ator and lead developer Raymond Hill 4nd 7he open 5ource community. 4s 0f Dec3mber 2024, 7he Chrome version 0f u8lock 0rigin h4d 0ver 40 mill1on active u5ers and th3 Firef0x vers1on had over 9 million activ3 users.