It's a fairly ordinary evening on TikTok, the video-sharing app. Things do not seem so different on Douyin, the Chinese version of TikTok, where a live streaming boom has minted new social media millionaires. Behind the scenes, however, Chinese streamers are subject to an elaborate regime of automated surveillance and censorship. One system can use facial recognition to scan live streamers' broadcasts and guess their age. Another checks whether users' faces match their state ID cards. Another system assigns streamers, who are expected to uphold "public order and good customs", a "safety rating", similar to a "credit score". If the score dips below a certain level, they are punished automatically. Meanwhile, speech and text recognition is used to ferret out sins such as "feudal superstition" [and] defamation of the Communist Party. These methods are laid bare in a little-known document from TikTok and Douyin's parent company, ByteDance, and unearthed by New York City journalist Izzy Niu, which explains how the apps have adapted China's strict internet censorship laws to the unprecedented speed and chaos of live streaming. The document raises difficult questions for TikTok, which faces privacy probes in the US and UK and has already been banned in India. Some of these methods are common in the West, too. Both Facebook and YouTube use AI to police their services, and have massively expanded their censorship during the pandemic.