How to Track AI Referral Traffic in GA4: ChatGPT, Perplexity and Gemini

AI referral traffic is the set of visits that begin when someone clicks a link inside an AI assistant answer, such as a ChatGPT citation, and lands on your website. GA4 can track part of it today. Create a custom channel group with an AI Assistants channel, match the source against a list of assistant names, and move it above Referral.

That gets you a clean report of visits from ChatGPT, Perplexity, Gemini, Copilot and Claude. It will not get you every visit, because some apps strip the referrer. Treat the numbers as a floor, and read this guide for the setup and the gaps.

How do you track AI referral traffic in GA4?

Open Admin, then Data display, then Channel groups, and create a custom group with a channel named AI Assistants. Add one condition that matches the session source against the assistants you care about, then drag the channel above Referral. Traffic acquisition will then show those visits as their own line.

Everything else in this guide is detail on those steps. Allow a day or two before you judge the report, and expect small numbers on most sites. For many businesses, AI assistants send a few visits a week, not a few hundred.

What counts as AI referral traffic?

It counts any session where GA4 can see that the visitor arrived from an AI assistant. That usually means a referrer such as chatgpt.com or perplexity.ai, or a utm_source value the assistant adds to the link. A click from an AI answer that passes neither signal looks like Direct traffic.

Three groups of visits sit outside that definition, and mixing them up is the most common reporting mistake:

• Clicks from Google AI Overviews and AI Mode. GA4 records these as organic search. Search Console is where they show up separately.
• Brand searches after an AI answer. Someone reads your name in an answer, then types it into Google. That visit is organic or direct.
• Visits from apps that hide the referrer. These land in Direct, and nothing in GA4 tells you which ones came from an assistant.

Does GA4 already have an AI Assistant channel?

Yes. Google’s release notes say that since 13 May 2026 Google Analytics assigns the medium “ai-assistant” when a referrer matches a recognised AI assistant, and files those visits under an AI Assistant channel in the Default Channel Group. Check your Traffic acquisition report before you build anything.

The Google Analytics release notes name ChatGPT, Gemini and Claude as examples. They do not list every assistant, so compare the built-in row with your Session source report for names such as perplexity or copilot. If a source you care about is missing, the custom channel below fills the gap.

How do you build an AI Assistants channel in GA4?

Go to Admin, Data display, Channel groups, and create a new group. It starts as a copy of the default group. Add a channel called AI Assistants, set the condition to Source matches regex, paste your list of assistant names, save the channel, then reorder so it sits above Referral.

Google’s own help page uses exactly this approach: its custom channel groups article includes an AI assistants example and recommends putting that channel above Referrals. Here is a starting expression you can adapt:

chatgpt|openai|perplexity|gemini|copilot|claude|grok|bard|mistral

The match is not case sensitive, so you do not need capital letters. The same help page says channel definitions cannot be edited after you save them, so write the list carefully, or plan to create a replacement channel when a new assistant appears.

Limits you should know about

A standard GA4 property can hold 2 custom channel groups, and a 360 property can hold 5. Each group can contain up to 50 channels, according to the same Google article. Those limits are generous for this job, but they matter if you already use a custom group for paid campaigns.

One useful detail: custom channel groups can be applied to your reports retroactively. You do not lose history by setting this up late. Your Traffic acquisition report can show the past months re-sorted by your new rules, as long as GA4 still holds that data.

Order matters more than the regex

GA4 puts each session in the first channel whose rule it matches. If Referral sits above AI Assistants, every ChatGPT visit is already claimed by Referral and your new channel stays empty. If you want AI Assistants to win over Organic Search as well, move it higher still.

How do you check AI visits in Traffic acquisition?

Open Reports, then Acquisition, then Traffic acquisition. Switch the primary dimension to your new channel group and read the AI Assistants row. Add Session source as a secondary dimension to split the row by assistant, and add Landing page to see which pages receive the visits.

If you would rather not wait for the channel group, search the Session source / medium report for the words chat, perplexity and gemini. That works on day one and also shows odd entries such as chatgpt.com / (not set), which usually means the referrer was missing. Both views are worth keeping, because they catch different things.

Which numbers to watch

Sessions are the weakest number here, because the totals are small. Look at engaged sessions, key events and landing pages instead. A single enquiry from an AI visitor tells you more than a month of session counts, and the landing page tells you which of your pages the assistants actually cite.

Review it monthly. Weekly checks on small numbers push people to read trends into noise.

What can GA4 not measure?

GA4 cannot see AI visits that arrive without a referrer, and it cannot see influence that never produces a click. Mobile app clicks, in-app browsers and some privacy settings remove the referrer, so those visits land in Direct. Your AI Assistants channel is a minimum, not a total.

Google’s AI features are the second gap. Clicks from AI Overviews and AI Mode are counted inside organic search in GA4, so your channel will not include them. To see how often your pages appear there, use Search Console: its generative AI performance report shows impressions from AI Overviews and AI Mode, and Google says it has been available to all websites worldwide since 31 August 2026. It reports impressions, not clicks.

Google also states in its AI features guide that there are no additional requirements to appear in AI Overviews or AI Mode. Standard SEO practice applies, so you cannot buy or tag your way into those answers.

The Search Console report also draws on the Web search type in your main Performance report, so the data sits next to your ordinary queries and pages. It will not show a click-by-click path, but it does tell you whether Google is showing your site in AI answers at all. The AI visibility tracking service covers the same question for assistants that give you no console.

From our work: We use Search Console exports to judge AI visibility for new sites. On the Evergee migration from WordPress to Astro, impressions in Google’s AI features a day went from under 10 to up to ~100 (Google Search Console exports, June to October 2026). Seeing your page in an answer and clicking it are different events, so we read impressions and visits side by side.

How do you log AI citations by hand?

Pick 10 to 20 questions your buyers ask, put each into ChatGPT, Perplexity and Gemini once a month, and record in a spreadsheet whether your brand is named, whether your page is linked, and which competitor appears. Date every row. That log shows visibility that no analytics tool captures.

Keep the method fixed so months are comparable. Use the same wording, a logged-out browser and the same country setting, and note that answers vary from run to run, so one result proves little. Look at patterns across the whole list instead.

A simple layout is one row per question and assistant, with these columns:

• Question and date
• Assistant used
• Brand named (yes or no)
• Your page linked (yes or no)
• Which other sites were cited

When a row shows your page linked, check GA4 for a visit around that time. You will rarely find one. When a competitor is linked and you are not, you have found a page to improve, and the SEO for Perplexity page explains what those assistants tend to pick up.

Keep the crawlers open

None of this works if assistants cannot read your pages. Check your robots.txt before you blame the analytics. Our guide to which AI crawlers to allow covers the main bots, and the generative engine optimization service page covers the wider work. Your core GA4 setup should be sound first, and our GA4 implementation guide walks through it.

Frequently asked questions

Get your AI traffic measured properly

If you want help setting up GA4, Search Console and a repeatable citation log, talk to LineUp. We will check your current tracking, build the AI channel, and tell you what is and is not measurable for your site.