Chinese internet giants including Alibaba, Tiktok-owner ByteDance and Tencent have shared details of their algorithms with China's regulators for the first time.
Algorithms decide what users see and the order they see it in - and are critical to driving the growth of social media platforms.
They are closely guarded by companies.
In the US Meta and Alphabet have successfully argued they are trade secrets amid calls for more disclosure.
The Cyberspace Administration of China (CAC) has published a list with the descriptions of 30 algorithms.
In a statement it said that its algorithm list would be routinely updated in a bid to curb data abuse.
Among the listed algorithms is one belonging to e-commerce website Taobao, owned by Alibaba.
The Mandarin document said Taobao's algorithm "recommends products or services to users through their digital footprint and historical search data."
ByteDance's algorithm for Douyin, China's version of TikTok, is said to gauge user interests through what they click, comment on, "like" or "dislike".