Manimatana Lee has spent the last five years building one of the internet’s hottest assets: a group of people who reliably watch her videos on TikTok.

She built an audience of nearly 10,000 followers with videos of her vacuuming her Wisconsin home while her youngest daughter was sleepy in a carrier on her back. A video of Ms Lee dancing and doing the dishes – while carrying her sleeping baby – has been viewed more than a million times since November.

Now, with the Supreme Court about to rule on a case that could decide whether TikTok could be banned in the United States on national security grounds, Ms. Lee and other Americans looking for alternatives are downloading Xiaohongshu, a popular in China Social media app China and little known outside the country.

“How funny would it be if they banned TikTok and we all just switched to this Chinese app,” Ms. Lee wrote on TikTok on Monday, encouraging her followers to join her.

Xiaohongshu was the most downloaded free app in the US Apple Store on Tuesday. Over 300 million people, especially in China, use the app and share both short videos and silent, text-based posts. The people who flocked there said in interviews and on the app that they wanted to show they did not share Washington’s concerns about TikTok’s ties to China.

TikTok, which is available in more than 150 countries but not China, is owned by Chinese internet company ByteDance. American YouTubers who post videos on TikTok say the app has been a source of connection, entertainment and information since it became a sensation during the Covid-19 pandemic. Its secret is its proprietary algorithm, a technology that recommends a constant stream of short videos to keep people scrolling.

But lawmakers in the United States and other countries have warned that the Chinese government could use TikTok to access data about its users such as location and browsing history. Officials in Washington say they are also concerned that China could use TikTok to spread false information among the 170 million people who use it in the United States.

Xiaohongshu means “little red book” in Mandarin. Americans new to the app said they were undeterred by the reference to a book of Mao Zedong’s sayings. Many people call the app “Red Note”.

“I don’t actually care if I even use a Chinese app,” Ms. Lee said. “For me it’s like a place where I can escape from reality. And if it makes me feel good, I’m here for it.”

A group of American YouTubers has sued the government over a law that could result in the TikTok app being forcibly sold or banned in the United States, and TikTok is paying their legal fees. Ms. Lee and another creator said in interviews that their interest in Xiaohongshu was not encouraged by either company. TikTok did not respond to a request for comment.

Americans on Xiaohongshu have rallied under the hashtag “TikTokrefugee,” which has been viewed 100 million times and sparked around 2.5 million discussion threads on the app as of Tuesday.

By joining the app, American users will have closer contact with online people in China than ever before on TikTok. In China they use Douyin, a very similar app that ByteDance used to develop the technology that made TikTok a global hit. Douyin is difficult to access outside of China.

Lots of shared tips for navigating the app, which is primarily intended for and used by those who read and speak Mandarin. Some took screenshots and asked ChatGPT to translate posts, they said.

Xiaohongshu displays the city or province of Chinese users posting and commenting, and the country for users outside of China. “We come to the Chinese spies and beg them to let us stay here,” said one American user. “Approved, welcome to Red Note,” someone in Shanghai replied.

According to Similarweb, a data provider and website traffic tracker, as of the end of December, 85 percent of Xiaohongshu traffic came from China. The app is particularly popular with women in their 20s and 30s, and its long comment threads, like Reddit, have become a popular source of information for exchanging questions about everyday concerns.

Xiaohongshu did not respond to requests for comment.

On Tuesday, more than 100,000 people had joined a live group chat moderated by a user called “TikTok Refugee Club” in which people from around the world chatted with Chinese users about urban security. In another group chat that was viewed more than 30,000 times, participants discussed censorship and gave tips in the comments on how to avoid being banned from the platform for addressing politically sensitive topics.

Under another video posted by someone who said they were usually on TikTok, a user in China responded with a meme of a cat with its paws outstretched. “I am your Chinese spy,” the comment said, “give me all your information.”