In what year did YouTube launch its dedicated music streaming service? YouTube launched YouTube Music in 2015. The dedicated app was unveiled in October and released for Android and iOS on November 12, 2015.
YouTube Music was designed specifically for music discovery and streaming. It combined official songs and albums with music videos, remixes, live performances, covers, and other music-related material from YouTube’s catalog.
In 2018, YouTube introduced a substantially redesigned version of YouTube Music, including a web player, improved personalization, and a separate subscription offering. That relaunch is likely the source of the incorrect 2018 answer.
The wording asks when YouTube launched its dedicated music streaming service, which points to the service’s original introduction rather than its later redesign. The correct year is therefore 2015.