How to track ChatGPT and Perplexity traffic in GA4
GA4 has an AI Assistant channel since May 13, 2026. How to find ChatGPT and Perplexity visits, and build a custom AI channel group with the regex to paste.
LLaunchScaler·Published ·7 min read
GA4 has tracked AI assistant visits on its own since May 13, 2026: its Default Channel Group now includes an AI Assistant channel, and when a visit's referrer matches a recognized assistant such as ChatGPT, Gemini or Claude, GA4 sets the medium to ai-assistant and the campaign to (ai-assistant). Open Reports, Acquisition, Traffic acquisition to see it.
A custom channel group is still worth building, because it can reclassify your data from before May 13, 2026, lets you choose exactly which sources count, and can split ChatGPT from Perplexity. Below are both, with the regex to paste, checked in September 2026.
Does GA4 have a built-in AI channel?
Yes. Google announced "New AI Assistant traffic measurement" on May 13, 2026. GA4 assigns the medium ai-assistant "when the referrer matches a recognized AI Assistant," files those visits under the AI Assistant channel, and names the campaign (ai-assistant). Google's channel description lists "ChatGPT, Gemini, Deepseek, Copilot, or Grok" as example sources.
Two limits are written into the definition:
It "excludes Google's AI Overviews and AI Mode." Clicks from those stay in Organic Search, which Google's Organic Search description now says includes them.
It depends on the referrer. A visit that arrives with no referrer cannot be matched, so it lands in Direct.
Default channel groups cannot be edited, so you cannot add a source Google's list misses. That is one of the reasons for the custom group below.
Where do you see ChatGPT and Perplexity traffic in GA4?
In the Traffic acquisition report. Open Reports, then Acquisition, then Traffic acquisition. The default table groups sessions by Session primary channel group, and AI Assistant appears as its own row once you have data. To see each engine separately, change the dimension to Session source / medium and search for the engine's domain.
Questions, answered
What people ask about this
01
Does GA4 track ChatGPT traffic?
Yes. Since May 13, 2026, GA4's Default Channel Group includes an AI Assistant channel. When the referrer matches a recognized AI assistant such as ChatGPT, Gemini or Claude, GA4 sets the medium to ai-assistant and the campaign to (ai-assistant).
Set the date range to include at least a few weeks after May 13, 2026.
Find the AI Assistant row for the total.
Click the dimension dropdown and choose Session source / medium.
Type chatgpt in the search box above the table to see the rows whose source is chatgpt.com, then repeat for perplexity, claude, gemini and copilot.
Add your key events as a column to see which assistant sends visitors who sign up. Setting those up is covered in how to track signups by source in GA4.
Why build a custom AI channel group as well?
Because it does three things the built-in channel cannot. Google says custom channel groups "can be applied to your reports retroactively," so you can see AI traffic before May 13, 2026. You control the list of sources. And you can create one channel per engine, instead of one total.
GA4 standard properties allow 2 custom channel groups in addition to the default one, with up to 50 channels each, so one group for AI analysis fits comfortably.
How do you create an AI channel group in GA4?
Copy the default group, add an AI channel matched on source with a regex, and move it above Referral. Google's own instructions follow this shape, and it notes that "Traffic is included in the first channel whose definition it matches," so the order is what keeps AI visits out of Referral.
In Admin, under Data display, click Channel groups. You need the Editor role or higher.
Click Create new channel group. GA4 starts you with a copy of the default group.
Name it, for example "Channels with AI split."
Click Add new channel and name it "AI assistants."
Click Add condition group, choose the dimension Source, the operator matches regex, and paste the regex below.
Click Save channel.
Click Reorder, drag "AI assistants" above Referral (and above Organic Search if you want it to take precedence there), then click Apply.
Two rules from Google's regex documentation shape it. GA4 uses full-match regex by default, so without the .* at each end the pattern would only match a source that is exactly one of those domains, and would miss www.perplexity.ai. And the dots are escaped with \. so they match a literal dot rather than any character. Channel definitions are not case sensitive, so capitalisation does not matter.
Your copy of the default group also contains Google's AI Assistant channel, defined as the medium exactly matching ai-assistant. Keep your channel above it. Because GA4 changes only the medium and campaign of assistant visits, not the source, a rule on Source catches the same visits before and after May 13, 2026, which is what makes the historical comparison possible.
Google's help page offers its own example regex for AI assistants. It uses loose terms such as .*gpt.* and .*ai, which can catch unrelated sources that happen to contain those letters. Listing exact domains is stricter; add a domain to the list when a new assistant starts sending you traffic.
How do you split ChatGPT from Perplexity in the channel group?
Create one channel per engine instead of one "AI assistants" channel, each with its own regex, all placed above Referral. The Traffic acquisition report then shows ChatGPT, Perplexity, Claude, Gemini and Copilot as separate rows when you select your custom group as the primary dimension.
Channel name
Condition: Source matches regex
ChatGPT
.*(chatgpt\.com|chat\.openai\.com).*
Perplexity
.*perplexity\.ai.*
Claude
.*claude\.ai.*
Gemini
.*gemini\.google\.com.*
Copilot
.*copilot\.microsoft\.com.*
To view the result, open Traffic acquisition, click the dimension dropdown and pick your custom group's name. Google says custom groups work as a primary dimension "in reports that already support the default channel group," as a secondary dimension in default reports, and in explorations and audiences.
How do you check that the channel group is working?
Compare it with the built-in channel for a period after May 13, 2026, then look for assistant traffic it missed. If your custom AI channel and Google's AI Assistant channel report similar sessions for the same weeks, the regex is catching what GA4 recognises. If yours is much lower, a domain is missing from the list.
Open Traffic acquisition and pick your custom group as the primary dimension. Note the AI total for the last 28 days.
Switch back to Session primary channel group and note the AI Assistant total for the same dates.
Switch to Session source / medium and filter for the Referral channel. Scan the sources for anything that looks like an assistant or AI search tool and is not in your regex.
Add any domain you find to the regex, save the channel, and check again next month.
Extend the date range back before May 13, 2026. Your custom group should now show AI sessions from those earlier weeks as well.
Does ChatGPT tag its links with UTM parameters?
Yes. OpenAI's publisher FAQ says "ChatGPT automatically includes the UTM parameter utm_source=chatgpt.com in referral URLs." That tag survives even when a browser or app drops the referrer, which is why a source-based rule catches ChatGPT visits that a referrer-only rule might miss.
Other assistants do not document a tag. If you share links in places you control, such as your own posts in communities or newsletters, use your own UTM parameters with consistent naming so those visits are not mistaken for assistant referrals; the conventions are in UTM parameters: a naming convention that holds up.
Why does GA4 undercount AI traffic?
Because some AI visits reach you with no referrer and no UTM tag, and GA4 files those as (direct) / (none). Google lists the causes: links without UTM parameters, redirects that strip them, URL shorteners, links opened from offline documents, and ad blockers that interfere with the cookies GA4 uses to identify a source.
For AI traffic that means visits from desktop or mobile apps that pass no referrer, answers a user copies and pastes into a new tab, and anything opened from a document are all at risk of landing in Direct. No channel group can recover a source that was never sent. Treat your AI numbers as a floor, and watch the trend rather than the absolute count. How GA4 decides between Referral and Direct in general is covered in referral traffic in GA4.
What does GA4 not tell you about AI visibility?
It shows who clicked, not who saw you. An answer that names your product and never links, or an answer the reader trusts without clicking, leaves no trace in analytics. For Google's AI features, Search Console's generative AI performance report counts impressions of your links in AI Overviews and AI Mode, and it reached all sites on August 31, 2026.
For ChatGPT, Perplexity and Claude there is no impression report, so run your own set of buyer questions each month and record whether you are named and linked. The method, and how to read the noise between runs, is in how to measure AI visibility.
Make sure AI engines can reach the pages they send traffic to
Referral traffic only comes from pages the engines can fetch and quote. Run the free scan on LaunchScaler to check that: it takes a URL, needs no account and runs 156 checks across 6 of its 7 categories at no cost. Its AI visibility checks read whether robots.txt or a firewall blocks OAI-SearchBot, Claude-SearchBot or PerplexityBot, whether ChatGPT-User and Claude-User get a real page or a challenge, and whether your main content is missing from the HTML those crawlers read.
Open Reports, then Acquisition, then Traffic acquisition, and look for the AI Assistant row in the Session primary channel group. For individual engines, switch the dimension to Session source / medium and filter for chatgpt.com or perplexity.ai.
03
Why does ChatGPT traffic show as direct in GA4?
Visits arrive as (direct) / (none) when no referrer or UTM tag survives the click, for example from some desktop and mobile apps, copied links, redirects that strip parameters, or ad blockers. Expect GA4 to undercount AI traffic for that reason.
04
Does ChatGPT add UTM parameters to links?
Yes. OpenAI says ChatGPT automatically includes utm_source=chatgpt.com in referral URLs from ChatGPT search results.
05
Are AI Overviews counted in GA4's AI Assistant channel?
No. Google says the AI Assistant channel excludes AI Overviews and AI Mode; clicks from those count as Organic Search. Search Console's generative AI performance report shows impressions from them instead.
AI answers lean on reviews, listings and comparisons because buyer questions are comparative. What the citation studies show, and which pages to be on.
