How to track AI search traffic in GA4: ChatGPT, Perplexity, Gemini and Claude

Where AI traffic shows up in GA4 today

Since May 2026, GA4's default channel group has an AI Assistant channel. When a visitor arrives from a recognised assistant, GA4 sets the medium to ai-assistant and files the session there instead of under Referral. Google names ChatGPT, Gemini, DeepSeek, Copilot and Grok as examples, but it has not published the full list or how often it is updated.

Two kinds of AI traffic never reach that channel. Clicks from Google's own AI Overviews and AI Mode arrive from google.com and are counted as Organic Search. And visits that arrive with no referrer and no tracking tag, which is common from mobile apps, land in Direct. That is why the AI Assistant channel is best read as the minimum amount of AI traffic you receive, not the total.

Step 1: Check the built-in AI Assistant channel

Open Reports, then Acquisition, then Traffic acquisition, and make sure the primary dimension is Session default channel group. If assistants are sending you visitors, AI Assistant appears as its own row next to Organic Search, Direct and Referral.

Add Session source as a secondary dimension to see which assistants they came from, and switch the table to Landing page to see which pages the assistants are citing. Those landing pages are your best evidence of which content AI tools already trust.

Step 2: Build a custom channel group for wider coverage

A custom channel group lets you decide the rules yourself, so you can include assistants Google's list misses and keep the definition stable when the default changes. Custom channel groups also apply to your historical data, so you can see AI traffic from before the built-in channel existed.

In GA4, go to Admin, then Data display, then Channel groups, and create a new group by copying the default one. Add a channel called AI assistants, set the condition to Session source matches regex, and paste a pattern like the one below. Then drag the new channel above Referral, because GA4 assigns each session to the first channel whose rules it matches.

• Regex to start from: .*(chatgpt|openai|perplexity|claude|anthropic|gemini\.google|copilot|deepseek|grok|meta\.ai|mistral|you\.com).*
• Keep it case-insensitive by matching lowercase source values, which is how GA4 stores referrer domains
• Review it every quarter and add any new assistant you spot in your Referral report
• Standard GA4 properties allow two custom channel groups, so name this one clearly, for example Channels with AI

Why ChatGPT traffic dipped in October 2026

Since mid-2025, ChatGPT has added utm_source=chatgpt.com to the links it shows, and that tag is the main way GA4 recognises a ChatGPT visit, because the browser often does not pass a referrer. After GPT-6 rolled out on 7 and 8 October 2026, many of those links lost the tag and opened without a referrer, so GA4 filed the visits as Direct.

Adobe's Cedric Huesler compared about 500 pages and found ChatGPT traffic down by roughly 31,000 visits a day while Direct rose by roughly 26,000 a day, which points to lost labels rather than lost visitors. OpenAI told him the missing tags were a known bug, and Search Engine Land reported that a fix began rolling out on 15 October, with tagged clicks back to about 95 to 100 percent of earlier levels.

The fix only applies to new clicks. Sessions from 8 to 15 October stay in Direct, so add an annotation for that week in your reports and avoid judging your AI visibility on it. Compare Direct traffic on the pages ChatGPT usually sends visitors to, and you will usually see the missing sessions there.

The AI traffic GA4 cannot see

Some AI influence never shows up as a session at all. Someone reads an answer in ChatGPT that mentions your company, then types your name into Google a day later, and GA4 records an organic or direct visit. Others copy your URL from an AI app into their browser, which arrives as Direct.

For Google's AI features, Search Console is the better source. In June 2026 Google started rolling out generative AI performance reports that show how often your pages appear in AI Overviews, AI Mode and Discover. They launched for a subset of sites first, show impressions rather than clicks or queries, and the same data is still included in the main Performance report.

• A rise in Direct traffic to deep pages, such as a blog post or service page, often means AI or app referrals that lost their source
• Branded search growth in Search Console can reflect people who first met your brand in an AI answer
• Asking prospects how they found you fills the gaps that analytics cannot

Connect AI visits to leads in your CRM

Sessions only matter if they turn into conversations. Capture the source, medium and landing page in hidden fields on your forms and booking pages, store the first touch on the contact record, and you can report on how many leads and deals started with an AI assistant.

Add an option such as ChatGPT or another AI assistant to your How did you hear about us question as well. Self-reported answers often show AI influence that analytics files as Direct or Organic. If you already pass ad clicks back to Google and Meta, the same fields feed that loop too, as we cover in our guide to offline conversion tracking.

What to report every month

A short, consistent report beats a complicated one that nobody reads. These are the numbers we track for clients who want to know whether AI search is worth their effort.

• AI assistant sessions by source, from both the built-in channel and your custom group
• Key events and conversions from those sessions, such as form fills and booked calls
• The top landing pages for AI traffic, which show what the assistants are citing
• Direct traffic to deep pages, with known tracking problems such as 8 to 15 October 2026 annotated
• A manual check of ten questions your buyers ask, run in ChatGPT, Perplexity and Gemini, noting whether you are mentioned

Turn the numbers into better visibility

The pages that already earn AI traffic tell you what works. Look at how they open, how clearly they answer the question in the first paragraph, and whether they carry FAQ sections and structured data, then bring your other key pages up to the same standard.

If assistants rarely send you visitors, the fix is usually content and structure rather than tracking. Our guide to getting cited by ChatGPT and Google AI Overviews covers the content side, and schema markup for AI search covers the technical signals that help engines understand your pages.

Frequently asked questions