Feishu said WeChat did not provide advance notice of the ban, adding that the move has “significantly affected work efficiency and user experience” at a time when many companies in China have moved their office operations online to limit the spread of coronavirus infections.

Instead, users need to copy the link and open it in a browser, instead of opening the app directly via WeChat.

Tencent launches new social apps as flagships WeChat and QQ show their age

A WeChat representative declined to comment other than to cite the company’s regulations on external links. The rules, introduced in October 2019, said the platform will punish websites or apps that send links to “mislead or entice users to download or redirect to an external app”. Punishment includes blocking their domain name from opening in WeChat.

Xie Xin, a ByteDance vice-president overseeing Feishu, said the app does not support sign-ups using a WeChat account nor does it enable the sharing of documents or messages on the Tencent app.

In addition to blocking the ByteDance app, WeChat also suspended two tech-focused media websites, 36Kr and ITHome, from publishing posts on the platform after they reported the Lark case over the weekend. The relevant articles have also been removed from WeChat.

The WeChat representative said it did not force media to delete their articles. Rather, the media in question have violated WeChat’s rules on multiple occasions.

The enterprise collaboration industry in China, which has received a huge boost from the health crisis, is forecast to achieve a compound annual growth rate of 12.4 per cent over five years to reach nearly 49 billion yuan (US$7 billion) by 2024, according to the Qianzhan Industry Research Institute.

The world’s biggest online population is staying home and China’s internet can’t cope

Feishu is a small but fast-emerging player in that sector, jumping 40 places from late January to become the 15th most downloaded business iOS app on Monday. However, it still lags far behind Alibaba Group Holding’s DingTalk as well as Tencent's WeChat Work and Tencent Meeting, which ranked as the top three among business iOS apps in China as of Monday, according to App Annie.

Alibaba is the parent company of the South China Morning Post.

In contrast, Tencent allows the sharing of links for JD.com and Pinduoduo pages, online retail marketplaces in which the company owns a financial stake.

How ByteDance is copying Tencent’s playbook to conquer gaming

“Having more than 1 billion users, [WeChat] has a monopolistic position in the market,” said Wang Sixin, a professor at the Communication University of China who specialises in media policy and rules. “Under these circumstances, Tencent has to have legitimate reasons to block other apps, otherwise it’s taking advantage of its dominance to force out smaller rivals.”