is supergirl in the same universe as flash and arrow
Arrowverse The first television series was Arrow, based on the character Green Arrow, which debuted in October 2012. The universe was expanded with the series The Flash in October 2014, which is based on Barry Allen / Flash. The universe expanded further in August 2015 with the animated series Vixen on The CW Seed, and again with the live-action team up series Legends of Tomorrow in January 2016. The franchise has also crossed over with DC Comics television shows which air on other networks; Arrow crossed over with the short-lived NBC series Constantine in the former's fourth season, while there have been multiple crossovers with the Supergirl TV series, primarily following its move from CBS to The CW.
Crisis on Earth-X Filming of the four episodes began on September 22, 2017.[16] Supergirl's episode was directed by Larry Teng, Arrow's by James Bamford, The Flash's by Dermott Downs, and Legend of Tomorrow's by Gregory Smith.[1]