Health codes are based on real data and can be generated by citizens or people who have returned to work through online declaration and background audit. As an individual entering and leaving electronic certificate locally, the QR code can be declared once, which is universal in the whole city.
On the evening of March 4, 2020, Jiangsu Health Code was officially launched. This also means that the Yangtze River Delta is the first in China to achieve full coverage of health codes: Shanghai, Jiangsu, Zhejiang and Anhui have all introduced provincial health codes.
As of March 5, 2020, Tencent's epidemic prevention health code was launched for 25 days, with a cumulative bright code of 654.38 billion times, covering more than 800 million people and a cumulative visit of 4.3 billion times. It is a health code that serves most users.