Finding 20 companies in the reCaptcha market

Finding 20 companies in China's reCaptcha market (emails and WeChat numbers).

Captchas (Completely Automated Public Turing test to tell Computers and Humans Apart) are designed to distinguish a bot from a human—the most notable example being Google’s reCaptcha, which asks users to identify objects in images to enter a website. There are at least 152 active services, mostly based in China, with more than half a million people working in the reCaptcha market, according to a 2019 study by researchers from Zhejiang University in Hangzhou.