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How to measure ChatGPT and AI search traffic in GA4

GA4 now has an AI Assistant channel. Here's how to use it, add a custom channel group with regex, and see what GA4 still can't tell you.

Simply Works teamThe Simply Works team, Chicago & Denver7 min read
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On this page10 sections
  1. How AI referrals reach your analytics
  2. What GA4 does out of the box now
  3. Step 1: Check GA4 AI traffic in the default report
  4. Step 2: Build a custom channel group with regex
  5. Step 3: Tie it to key events
  6. Step 4: See which pages AI tools send people to
  7. What GA4 can't see
  8. Filling the gaps outside GA4
  9. What we'd do
  10. Frequently asked questions

Short answer

Since May 2026, GA4 sorts visits from AI assistants like ChatGPT, Gemini and Claude into a built-in AI Assistant channel. Use it, add a custom channel group with a regex so you have one consistent definition across your history, and tie it to your key events. Remember that clicks from Google's AI Overviews and AI Mode count as Organic Search, so GA4 AI traffic numbers will always undercount AI's real influence.

People ask us two questions about AI search: "Are we showing up?" and "Is it sending us anything?" The first is hard to answer. The second, you can mostly answer in Google Analytics 4 in about twenty minutes. This guide covers how to find GA4 AI traffic, how to build a channel you control, how to connect it to leads, and the blind spots to keep in mind.

How AI referrals reach your analytics

When someone clicks a link in a ChatGPT answer, a Perplexity result or a Gemini response, their browser usually passes along where they came from. GA4 records that as the session source, like chatgpt.com or perplexity.ai. OpenAI also says that ChatGPT automatically adds utm_source=chatgpt.com to referral links, which makes its traffic easier to spot even when the referrer is missing.

Until recently, all of this landed in the Referral channel, mixed in with links from directories, partners and random blogs. That changed this spring.

What GA4 does out of the box now

On May 13, 2026, Google Analytics added a dedicated AI Assistant channel to the default channel group. Per the release note, GA4 now sets the medium to ai-assistant and the campaign to (ai-assistant) when the referrer matches Google's list of AI assistants, and groups those sessions under AI Assistant. Google's channel definitions describe it as the channel by which users arrive "from sources like ChatGPT, Gemini, Deepseek, Copilot, or Grok."

A month later, on June 11, GA4 added a Source group dimension that consolidates messy source values, with built-in grouping for sources like ChatGPT (OpenAI) and Perplexity.

Two caveats:

  • Google's list is Google's list. It doesn't publish every referrer it matches, and new AI tools appear constantly.
  • Don't assume the new channel covers your history. If your year-over-year view shows AI sessions sitting in Referral before mid-May, that's the old classification. A custom channel group gives you one definition across both periods.
Where AI-driven visits land in GA4 Visits from ChatGPT, Gemini and Claude go to the AI Assistant channel with medium ai-assistant. AI tools not on Google's list go to Referral until a custom channel group catches them. Clicks from Google AI Overviews and AI Mode go to Organic Search, mixed with regular Google search. Visits from apps and copied links go to Direct because no referrer is passed. WHERE THEY CLICKED WHERE GA4 PUTS IT ChatGPT, Gemini, Claude AI Assistant medium: ai-assistant AI tools not on the list Referral until your custom group AI Overviews, AI Mode Organic Search mixed with regular Google Apps, copied links Direct no referrer passed
Fig. 01Where AI-driven visits land in GA4: only some of them show up as AI Assistant, and clicks from Google's own AI features count as Organic Search.

Step 1: Check GA4 AI traffic in the default report

Start with what's already there.

  1. Go to Reports > Acquisition > Traffic acquisition.
  2. Make sure the table's primary dimension is Session primary channel group (Default channel group).
  3. Look for the AI Assistant row. If it's missing, you either have no recognized AI visits in the date range or the range is before May 13, 2026.
  4. Click the + next to the dimension name and add Session source as a secondary dimension to see which assistants are sending visits.

Set the date range to the last 28 or 90 days. AI referral volumes are usually small for local businesses, so short ranges are noisy.

Step 2: Build a custom channel group with regex

A custom channel group lets you define AI traffic your way and apply it to past data. Google's help page says custom channel groups can be applied to your reports retroactively, and standard properties can create two of them in addition to the default. You'll need the Editor role or higher.

  1. Go to Admin, then under Data display choose Channel groups.
  2. Click Create new channel group. GA4 starts you with a copy of the default group.
  3. Name it something like "Channels with AI."
  4. Click Add new channel and name it "AI tools."
  5. Add a condition: Source matches regex, and paste the pattern below.
  6. Save the channel, then reorder it so it sits above Referral. Google is explicit that traffic goes into the first channel whose definition it matches, so order matters.
  7. Save the group.

Here's the pattern we use as a starting point:

.*(chatgpt|openai\.com|perplexity|gemini\.google\.com|copilot\.microsoft\.com|claude\.ai|deepseek\.com|grok\.com|meta\.ai).*

A few notes on it:

  • In GA4, "matches regex" has to match the whole value, which is why the pattern starts and ends with .*. If you choose "partially matches regex" instead, you can drop those.
  • chatgpt without a domain catches both chatgpt.com and the UTM version of it.
  • The dots are escaped (\.) so they mean a literal dot.
  • Review your Referral sources every quarter and add any new AI tools you see.

Google's own help page includes an example AI pattern too. We prefer a tighter list of named domains, because broad fragments like ai or gpt can sweep in unrelated sites.

Once saved, go back to the Traffic acquisition report, open the dropdown for the table's primary dimension, and switch it to your new channel group.

Step 3: Tie it to key events

Visits are interesting. Leads pay the bills. Make sure the actions that matter are marked as key events, which is what GA4 now calls what it used to call conversions: form submissions, quote requests, calls from the site, bookings, purchases.

Then, in Traffic acquisition, use the dropdown under the Key events column to pick the event you care about and see it by channel. The question to answer each month is simple: how many leads came from AI tools, and how does their conversion rate compare to organic search? For most local businesses the volume is small. What matters is whether those visitors turn into customers.

Step 4: See which pages AI tools send people to

This one is useful for content decisions.

  1. Go to Explore and create a Free form exploration.
  2. Add dimensions Landing page + query string and Session source.
  3. Add metrics Sessions and Key events.
  4. Put Landing page in rows and Session source in columns, or add a filter: Session source matches regex, using the pattern above.

You'll usually find that AI tools send people to a handful of pages: a specific service page, a pricing explainer, a how-to guide. Those are the pages AI systems find quotable. Look at what they have in common and do more of it.

What GA4 can't see

This is the important part. GA4 only knows about visits that arrive with a recognizable source. A lot of AI influence doesn't.

  • Google's AI Overviews and AI Mode. Google's channel definitions say Organic Search includes clicks from "Google's AI Overviews and AI Mode." GA4 can't separate them from regular Google clicks.
  • Apps and copied links. Some apps don't pass a referrer, and people often copy a business name or URL from an answer and type it in. Those visits show up as Direct.
  • Brand searches after an AI answer. Someone reads a ChatGPT answer that mentions you, then searches your name on Google. GA4 credits Google.
  • Answers with no click. If an AI tool recommends you and the person calls you straight from your Business Profile, GA4 never sees a session.

So treat the AI Assistant number as a floor, not the full picture.

Filling the gaps outside GA4

  • Search Console. Google says traffic from AI features is included in your Performance report totals. In June 2026, Google announced a Generative AI performance report showing impressions in AI Overviews and AI Mode by page, starting with a small group of UK site owners. Check whether you have it yet.
  • Bing Webmaster Tools. Microsoft added an AI Performance report in public preview in February 2026, showing how often your pages are cited in Copilot and Bing's AI summaries. It's free and worth setting up.
  • Ask people. Add "AI assistant (ChatGPT, Gemini, etc.)" as an option to your "How did you hear about us?" field. Self-reported data is imperfect, but it catches the influence analytics misses.

What we'd do

If you want the short version:

  1. Check the AI Assistant row in Traffic acquisition today.
  2. Build the custom channel group with the regex above, placed above Referral.
  3. Confirm your lead actions are key events.
  4. Build the landing page exploration and save it.
  5. Set up Bing Webmaster Tools and watch for the Search Console AI report.
  6. Add an AI option to your intake forms.
  7. Review monthly, alongside the metrics that matter most. Our post on SEO KPIs that actually matter covers the rest of that dashboard.

Measurement tells you what's happening. Improving it is a content and visibility job; start with how to show up in ChatGPT answers and how to get cited in Google's AI Overviews. If you'd rather have us set up the tracking and the reporting, it's part of our SEO and local SEO service.

Frequently asked questions

Why is my AI Assistant channel empty?

Either no recognized AI tool has sent a visit in that date range, or the range ends before May 13, 2026, when the channel was added. Check Referral for sources like chatgpt.com to be sure.

Can I see which ChatGPT prompts sent visitors?

No. ChatGPT passes the source, not the conversation. You can see the landing page, which hints at the question.

Should AI traffic be its own goal?

Track it, but judge it by leads, not by sessions. A handful of visits that turn into quote requests beats a spike of visits that bounce.

Written bySimply Works teamThe Simply Works team, Chicago & Denver
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