[DigitalToday reporter Jinju Hong] ByteDance's flagship artificial intelligence (AI) chatbot app Doubao saw its monthly active users (MAU) fall by 6.1 million in May after it signalled it would introduce a paid subscription model.

Hong Kong's South China Morning Post reported on Tuesday that Doubao's MAU stood at 330 million in May, down 1.81 percent from the previous month.

Doubao showed a rare decline since its 2023 launch. Aicpb.com, a global AI market research firm, put the drop at 6.1 million users. ByteDance in early May updated Doubao's iOS page on Apple's App Store to unveil its first paid subscriptions. The standard plan is 68 yuan a month, or 688 yuan a year. The higher-tier "Professional" plan is priced at 500 yuan a month, or 5,088 yuan a year.

Some in the market said the timing was too early. Li Bangzhu (리방주), founder of Aicpb.com, called Doubao's decline a worrying signal, saying that in China's market the number of users decides everything. He said the era of free AI services in China still has a long way to go, and that Doubao could clearly be moving to monetise too early.

Doubao still holds its position as the most popular AI mobile app in China. But Qwen from Alibaba Group Holding, in second place, is quickly narrowing the gap. Qwen's MAU in May rose to 234 million, up by more than 13 million in a month. Its growth rate was 6.06 percent. The gap between the two apps is still close to 100 million users, but a warning has emerged that a company that charges first in a segment where switching costs are low could hand the initiative to rivals. Li said whoever charges users first could cede the lead to competitors.

This trend is not only a Doubao issue but shows a broader challenge for China's big tech. Consumers in China's internet market are still not actively paying for chatbot-based, everyday AI services. Most major apps, including Doubao, Qwen and DeepSeek, are also offered largely for free.

By contrast, companies' cost burdens are rising. Morgan Stanley analysts said in a report in early May that computing resources would need to increase significantly to meet demand for advanced agent-based AI, and that flat-rate free offerings are not economically sustainable in such an environment. They said demand among Chinese consumers for paid AI subscriptions has generally not yet been proven. For this reason, they viewed Doubao's monetisation timing as earlier than that of ChatGPT, which had MAU above 1 billion.

ByteDance is reportedly reviewing an expansion of monetisation. Chinese information technology media outlet 36Kr reported that ByteDance plans to introduce paid content on Doubao at the end of June. But a person familiar with the matter said the launch timing has not yet been confirmed and free functions will continue to be provided.

As a result, competition in China's AI app market is shifting from simply expanding users to testing revenue models. A key point to watch in the near term is whether Doubao will keep its lead while adjusting the pace of its shift to paid services, or whether it will hand more users to rivals promoting free strategies.