On 27 October 2018, Robert Bowers entered Tree of Life Synagogue in Pittsburgh, Pennsylvania and killed 11 people and wounded 6 others. The attack is believed to be the deadliest on the Jewish community in US history, according to the Anti-Defamation League. Prior to the shooting, Bowers had posted numerous messages on social media site Gab expressing hate against Jewish people, migrants, and refugees. 

Soon after the shooting, PayPal banned Gab from using its payment processing. Hours later, Stripe followed suit, as did Joyent, the company that provided cloud-hosting services for the social media site. GoDaddy, the domain name provider, told Gab it had 24 hours to move its domain name to another service, after finding content on the site that promoted violence. According to a New York Times article, in an email interview Gab's chief executive said that while he had not reviewed all of Mr. Bowers’s posts, the company had turned over information about his account to law enforcement agencies and was cooperating with the investigation.