The competitive landscape of generative AI witnessed a dramatic shift in late 2025, with Google's Gemini chatbot making significant gains against its rival, OpenAI's ChatGPT. Fresh data reveals a substantial surge in Gemini's user base, coinciding with a notable decline for ChatGPT, prompting internal alarms at OpenAI.
Traffic Trends Show a Dramatic Shift
According to analytics from Similarweb, Google's Gemini platform reported an impressive 28% month-over-month growth in December 2025. This growth propelled Gemini's web audience size to command close to 40% of rival ChatGPT's traffic. In a stark contrast, ChatGPT's own fortunes seemed to wane. Data indicated that ChatGPT's seven-day average visitor count fell by approximately 22% over a six-week period, dropping from nearly 203 million to around 158 million.
Reacting to these promising numbers, Google AI CEO Demis Hassabis acknowledged the progress while emphasizing the road ahead. He stated, "a lot more hard work still to do of course, but making relentless progress…" This comment underscores Google's determined push to expand Gemini's reach in an increasingly fierce market.
OpenAI's "Code Red" and Market Share Dynamics
The pressure on OpenAI became palpable soon after Google launched its advanced Gemini 3.0 model in November 2025. Internal memos obtained by The Wall Street Journal and The Information revealed that OpenAI CEO Sam Altman declared a "code red" emergency within the company. In response, Altman directed employees to halt work on various new features—including advertising, AI shopping assistants, health agents, and the Pulse personal assistant—and to refocus all efforts on improving ChatGPT's core product. "We are at a critical time for ChatGPT," Altman wrote in the memo.
While ChatGPT still leads in overall AI traffic, its market dominance is eroding. Similarweb data shows its share of the generative AI market fell from 68% in December 2025 to 64.5% by January 2, 2026. Gemini, on the other hand, has seen a meteoric rise from a 5.7% share a year ago to commanding 21.5% of the market.
Google's Full-Stack Advantage Proves Decisive
Analysts point to Google's deep-rooted infrastructure and ecosystem integration as key factors in Gemini's accelerating growth. Unlike its rivals, Google benefits from a vertically integrated "full stack" approach. This encompasses DeepMind's model research, proprietary TPU v5 chips optimized for Gemini (reducing costs and boosting performance), efficient hosting on Google Cloud, and seamless integration into products used by billions.
Gemini is embedded across Google's ecosystem, including Search, YouTube, Gmail, and on approximately 3 billion Android devices, providing a massive built-in user base. In contrast, OpenAI relies on Microsoft's cloud infrastructure and Nvidia's chips, which can create structural cost and agility disadvantages.
DeepMind CTO Koray Kavukcuoglu highlighted this strategic edge last year, noting, "One of the most important things for us at Google is this is possible because we have a very differentiated full-stack approach." This combination of enterprise trust, hardware synergy, and ubiquitous integration is proving to be a formidable advantage for Google as the AI wars intensify.
