Character.ai is closing in on ChatGPT on mobile

While the tech world obsessively debates which AI can write the cleanest Python code or summarize corporate earnings reports, everyday smartphone users are apparently using the technology for something else entirely: talking to imaginary friends.

New data from analytics platform Similarweb reveals that Character.ai is rapidly closing the gap with ChatGPT on mobile devices in the United States. Character.ai's iOS and Android apps reached 4.2 million monthly active users in the U.S., hot on the heels of ChatGPT's roughly 6 million U.S. mobile actives.

That is an eye-opening trajectory for an app that only launched on mobile app stores in May.

Gen Z lives on mobile, not inside spreadsheets

When Character.ai launched its mobile client, it logged 1.7 million downloads in week one. In typical app land, that usually means very little: Appsflyer benchmarks show average 30-day retention sits around 3% to 4%, with uninstall rates topping 40%.

Yet Character.ai managed to turn curiosity into genuine habit. While ChatGPT still dominates global reach—holding 22.5 million Android MAUs globally against Character.ai's 5.27 million, alongside massive web dominance—Character.ai holds an unmatched lock on the youth demographic.

Around 60% of Character.ai's web audience falls between the ages of 18 and 24. For ChatGPT, that younger demographic made up just 27% in July, down from 30% in April.

Other AI darlings lag even further behind among young adults. Perplexity registers 22.7%, Midjourney hits 22.3%, Anthropic lands at 25.3%, and Google Bard trails at 18.46%.

Summer slumps vs. around-the-clock fun

Demographics also explain why the summer season impacted the two platforms differently. Global visits to ChatGPT's website dipped for three consecutive months—falling 10% in June, 10% in July, and 3.2% in August to 1.43 billion—as students went on holiday and homework help took a backseat.

Average user session duration on ChatGPT also shrank from 8.7 minutes in March to 7 minutes in August. Numbers only started ticking back up in late August as school returned, with U.S. unique visitors edging up 3%.

Character.ai avoided that seasonal slump because users treat it as conversational entertainment, not a homework engine. While its browser traffic wobbled slightly, mobile downloads carried the weight.

The startup has serious muscle behind the scenes. Co-founders Noam Shazeer and Daniel De Freitas previously spearheaded Google's LaMDA project. Earlier this year, a16z led a $150 million Series A funding round that valued the business at $1 billion.

Why it matters

We think this shift proves a fundamental point about consumer AI: raw utility might make headlines, but emotional connection captures user retention.

For builders, Character.ai shows that you do not need to position an LLM as an enterprise co-pilot to build a billion-dollar product. Chatting with dynamic fictional personas turns out to be an incredibly sticky mobile behavior that fits neatly into daily screen time.

For the broader industry, it exposes the vulnerability of productivity-first platforms. Tools like ChatGPT remain susceptible to school schedules, workday cycles, and efficiency ceilings where faster completion actually cuts screen time. Entertainment and companionship apps, on the other hand, reward open-ended play.

The open question is staying power. Young audiences are notoriously fickle, and today's breakout companion app can easily become tomorrow's discarded digital fad. Character.ai also faces looming scrutiny around content guardrails and user attachment, which will test its technical foundations far beyond raw token speed.