How to See AI Referral Traffic in GA4

When an AI assistant recommends your brand, some buyers click through to your site. Google Analytics 4 records where each session came from in its Session source dimension, and this guide shows three ways to find them: a filter on the standard Traffic acquisition report, a free-form exploration, and a custom channel group that keeps AI visits apart in every report. All three use the same regular expression, which you can copy below.

The numbers are small but growing. Similarweb counted 1.13 billion referrals from AI platforms to the top 1,000 websites in June 2025, up 357 percent on a year earlier, with ChatGPT sending more than 80 percent of them. Google Search sent 191 billion referrals in the same month.

Menus as of 31 October 2026, checked against Google's own Analytics Help pages, which are linked in each step.

The regular expression

This pattern matches the web addresses of ChatGPT, Perplexity, Claude, Gemini and Microsoft Copilot, with or without a www. or other prefix in front:

^(.*\.)?(chatgpt\.com|chat\.openai\.com|perplexity\.ai|claude\.ai|gemini\.google\.com|copilot\.microsoft\.com|copilot\.com)$

Domains checked 31 October 2026, each on the vendor's own site: OpenAI's developer site links "Try ChatGPT" to chatgpt.com; Perplexity's getting started guide says to visit Perplexity.ai in your browser; Anthropic's help centre says to visit claude.ai to chat with Claude in a browser; Google's Gemini Apps Help says to go to gemini.google.com; and copilot.microsoft.com redirected to copilot.com, a Microsoft Copilot sign-in page, when we checked, so the pattern keeps both. The pattern also keeps chat.openai.com, an earlier ChatGPT address that may still appear in older data; we could not confirm it on an OpenAI page, so treat it as a safety net.

The pattern leaves out bing.com on purpose. Copilot answers shown inside Bing may arrive with bing.com as the source, but so does ordinary Bing search, so adding it would mix the two.

Three things about the pattern matter in GA4:

• Google's regex guide for Analytics says regular expressions in Google Analytics are full match and case sensitive by default. The ^ and $ make the full match explicit, and the (.*\.)? part lets subdomains through.
• The same guide says to escape a dot with a backslash so it is not read as a wildcard. That is why every dot above is written \..
• Google's report filter help says regular expressions there are limited to 250 characters. This one is well under that, so you can add more domains later.

Method 1: filter the Traffic acquisition report

This is the quickest view, and it needs no setup. The steps follow Google's Traffic acquisition report and report filter help pages.

1. In GA4, select Reports from the left menu.
2. Select Acquisition then Traffic acquisition.
3. Select the dimension picker at the top left of the table and choose Session source, as Google's page on changing dimensions in detail reports describes. The report's default dimension is Session default channel grouping.
4. Click + Add filter at the top of the report.
5. Choose Session source as the dimension.
6. In the Match Type field, choose matches regex.
7. Paste the regular expression into the text box and click Apply.

The table now shows only the sessions whose source matches one of the assistants, one row for each source. Google's filter page notes that you can only add filters to detail reports, so if you do not see + Add filter, you are on an overview report.

Method 2: build a free-form exploration

An exploration takes a few more clicks, but it lets you put other dimensions and metrics beside the source. The steps follow Google's help pages on getting started with Explorations, the free-form exploration and segments and filters.

1. Go to Explore and, under Start a new exploration, select the Free form template.
2. In the Variables column, click the add icon next to DIMENSIONS. Search for Session source, select it, then click Import.
3. Click the add icon next to METRICS and import a metric such as Sessions.
4. Drag Session source into Rows and the metric into Values in Tab Settings.
5. Scroll to the bottom of the settings panel to the Filters section. Click Drop or select dimension or metric and choose Session source.
6. Choose the match type for a regular expression, paste the pattern and click Apply.

Google's help page on segments and filters says expressions are case sensitive, and that when you add more than one filter, the data must meet all of them.

Method 3: add an AI channel to a custom channel group

Methods 1 and 2 are views you set up each time. A custom channel group makes AI referrals a channel of their own, next to Organic Search and Referral, in your standard reports. The steps follow Google's help page on custom channel groups, which says you need the Editor role or above on the property.

1. In Admin, under Data display, click Channel groups.
2. Create a group. If you have none yet, you start with a copy of the default channel group, which keeps all the standard channels.
3. Click Add new channel and name it, for example "AI assistants".
4. Click Add condition group, choose the source dimension, set it to matches regex and paste the regular expression above.
5. Save the channel, then click Reorder and drag "AI assistants" above Referral. Google's page says traffic goes into the first channel whose definition it matches, in the group's order, so a channel placed below Referral would never receive these visits.
6. Click Apply and save the group.

Google's page says custom channel groups can be applied to your reports retroactively, so earlier AI visits show under the new channel too. A standard property can have two custom channel groups besides the default one.

What to look at once it is set up

• Sessions by assistant, month on month. The trend matters more than the total.
• Landing pages. The pages AI visitors land on are the pages assistants link to. That tells you which of your content they treat as worth citing; how to get cited by ChatGPT covers how to earn more of it.
• Engagement and conversions against organic search. Compare like with like before judging the channel by its size.

What this will not show

Treat the number as a floor, not the full count.

• Visits without a referrer. Google's page on (direct) / (none) traffic describes direct traffic as traffic without a clear referral source, and lists causes such as redirects that strip UTM parameters, links in documents and ad blockers. Some visits from AI assistants may arrive that way too, and those would sit under direct rather than under the assistant's name.
• Google AI Overviews and AI Mode. These answers sit inside Google Search, so the pattern above does not cover them. Google's AI features and your website page says sites appearing in AI features are included in the overall search traffic in Search Console, in the Performance report under the Web search type.
• Buyers who never click. Some buyers get what they need from the answer itself, which is zero-click search. A buyer can hear your brand recommended, or hear a rival recommended instead, and never visit your site.

That last point is the big one. Referral traffic tells you about the buyers who clicked. It does not tell you about the conversation before the click, or about the buyers who were steered away. As what happens after the first answer explains, buyers ask an assistant several questions before they choose, and a brand can be named at the first and gone by the fourth.

Pair referral traffic with what the assistants say

Use the GA4 view to see whether AI visits are growing. Use answer tracking to see why. Vouch asks AI assistants the questions your buyers ask, follows each conversation for six questions, and records the stage where your brand stops being named and who is recommended instead. Killer questions explains how to find that stage, and our methodology sets out how each assistant is asked and scored. Plans and prices are on the pricing page.