utm_source=chatgpt.com: how to see ChatGPT and other AI traffic in GA4

Google Analytics 4 (GA4) can show visits from ChatGPT and other AI assistants, but it cannot count citations that never lead to a click. ChatGPT adds utm_source=chatgpt.com to the links in its answers. When someone clicks one, the tag travels in the web address to your site, so GA4, Google’s free website statistics tool, can record chatgpt.com as the source of the visit.

To find those visits, open Reports > Acquisition > Traffic acquisition. Look for the AI Assistant row, or change the table’s main dimension to Session source and search for chatgpt. The sections below cover reading individual sources, building your own AI channel and tracking the citations GA4 never sees.

What does utm_source=chatgpt.com mean?

A web address can carry extra information after a question mark. https://example.com/guide?utm_source=chatgpt.com opens the same page as https://example.com/guide; the part after ? gives your analytics a source label. Tags beginning with utm_ are called UTM parameters. Analytics tools use them to identify where a visitor came from, and utm_source names the sender.

OpenAI documents the tag in its Publishers and developers FAQ: “ChatGPT automatically includes the UTM parameter utm_source=chatgpt.com in referral URLs, enabling clear tracking and analysis of inbound traffic from ChatGPT search results.” The FAQ also names Google Analytics as a tool for tracking these visits.

The referrer is a second, older signal: the address of the page a visitor came from, passed along by the browser when they click a link. A UTM tag is part of the destination address itself. The referrer, by contrast, depends on the browser and on the rules of the page the visitor left. Under the default browser rule for links between different sites, only the domain is sent, not the full address (MDN). So the referrer tells you “chatgpt.com”, not the question the person asked.

OpenAI documents only utm_source. Google warns that missing UTM parameters produce (not set) values in reports. So if you see (not set) next to chatgpt.com, filter on the source rather than the medium.

Where do I see ChatGPT traffic in GA4?

There are three ways to inspect the traffic, from a channel total to a custom analysis.

1. The AI Assistant channel. On 13 May 2026, Google announced an AI Assistant channel in GA4’s default channel group. That group is the built-in set of labels, such as Organic Search, Referral and Direct, that GA4 uses to sort visits. Google defines AI Assistant as visits “from sources like ChatGPT, Gemini, Deepseek, Copilot, or Grok.” Open Reports > Acquisition > Traffic acquisition. The table is grouped by channel by default, so look for the AI Assistant row.
2. The search box. In the same report, change the table’s main dimension to Session source, the site or app that started the visit. Type chatgpt in the search box above the table, then repeat with perplexity, gemini, copilot and claude. This shows each assistant’s traffic separately.
3. An exploration. In Explorations, GA4’s free-form analysis area, filter Session source with a regex: a regular expression that matches several values with one pattern. Google notes that exploration filters are case sensitive.

Google’s AI Overviews and AI Mode, the AI-written answers inside Google Search, are not in the AI Assistant channel. Their clicks count as Organic Search alongside ordinary Google clicks. Search Console’s Generative AI performance report covers those features. It shows impressions, meaning how often links to your site appeared in them, rather than visits.

If every AI row reads zero, check crawler access. OpenAI links the tracking to publishers “who allow OAI-SearchBot”. OAI-SearchBot is the crawler that reads web pages for ChatGPT’s search feature. Your site’s robots.txt file tells crawlers what they may read. GPTBot vs OAI-SearchBot vs ChatGPT-User explains which robots.txt switch does what.

How do I build my own AI channel?

GA4 lets you copy the default channel group and add channels of your own. A custom AI channel makes the source rules visible and puts them under your control. That matters because Google does not publish its list of AI assistants: the downloadable source list linked from its channel documentation contains search, social, shopping and video categories, but no AI category (checked 24 September 2026).

Follow these steps from Google’s custom channel groups help page:

1. Go to Admin > Data display > Channel groups. You need the Editor role or higher.
2. Click Create new channel group. GA4 starts you with a copy of the default group.
3. Click Add new channel and name it AI assistants. Add a condition: Source, matches regex, then paste the pattern below.
4. Click Reorder and drag your channel above Referral. GA4 assigns each visit to the first matching channel, working from the top down. If Referral matches first, the visit stays there.
5. Click Save group. Then select your group as the dimension in the Traffic acquisition report.

Google says custom channel groups “can be applied to your reports retroactively”, so your new channel also sorts past visits. A standard property can hold two custom groups, each with up to 50 channels.

The copy-paste regex

.*(chatgpt|perplexity|claude|gemini|copilot|deepseek|grok).*

Every assistant in this pattern is named in Google’s GA4 documentation. Keep the .* on both sides: GA4 regex is full-match by default. Without those wildcards, the pattern would match a source called exactly chatgpt, but not chatgpt.com.

Check your source list before relying on the channel. The pattern deliberately matches parts of names, so an unrelated site whose name contains one of these words will match too. If that happens, replace the word with the exact domain you see in your data, for example chatgpt\.com. Your own property tells you which assistants send visits and which source names they use.

Google’s custom channel groups page offers a broader example pattern for an AI channel. Its first part, ^.*ai, matches any source ending in the letters “ai”. Use it for a first look, then narrow it to the sources you find.

What can GA4 not show you?

Use this table to separate what GA4 records from what needs another form of measurement.

You want to know	Does GA4 show it?	Why not, or where to look
How many people clicked a link in a ChatGPT answer	Yes, as visits with source chatgpt.com	Only clicks that reach your site and that your cookie settings let GA4 record
How often ChatGPT cited or named you	No	A citation without a click never touches your site. Keep a manual log of questions and answers
Which question the person asked	No	Browsers pass the domain, not the conversation
Clicks from Google AI Overviews and AI Mode	Mixed into Organic Search	Search Console’s Generative AI performance report shows impressions, not visits
Readers who copied your address into a new tab	Counted as Direct	Google’s Direct channel covers links typed in or saved
Visits from an assistant that adds no tag and whose app sends no referrer	Counted as Direct	Whether an app passes a referrer is up to that app

A person can read and trust an answer based on your page without visiting your site. A citation or mention alone creates no session. ChatGPT mentions vs citations explains the distinction between those two events. How to get cited by ChatGPT covers the page work that makes a citation more likely.

A worked example (hypothetical)

Imagine a small bike-repair shop in Utrecht with a well-read guide to finding a slow puncture. In September, the owner opens Traffic acquisition and sees 14 sessions in the AI Assistant row. She changes the dimension to Session source and searches for chatgpt: 11 sessions. The other three came from Perplexity.

Each of those 14 sessions began with a click in an AI answer. A session is one visit; one person can make several. The count says nothing about readers who saw an answer based partly on the guide and never clicked. It also says nothing about whether the answer got the repair right.

The owner adds her own AI assistants channel, so the count follows rules she can inspect. She also starts a weekly note: three questions asked in ChatGPT with search switched on, and two columns, “named” and “linked”. GA4 records visits. The note tracks mentions and citations. Neither replaces the other.

Try this today (ten minutes)

1. Minutes 0 to 2. Open Reports > Acquisition > Traffic acquisition and set the date range to the last 90 days. Record the AI Assistant session count, even if it is zero.
2. Minutes 2 to 5. Change the main dimension to Session source. Search for chatgpt, then perplexity, gemini, copilot and claude. Record each source exactly as it appears.
3. Minutes 5 to 9. Create the AI assistants channel with the regex above, move it above Referral and save.
4. Minutes 9 to 10. Pick the page with the most AI visits. With search switched on, ask ChatGPT the question that page answers. Note whether it names you and whether it links to you.

This is the measurement half of being findable. My book on this subject, The Findability Engine, is in production and not for sale yet. The GEO glossary entry has the short version of the wider job.

Keep the visit count and the citation log side by side. A reader can find your work useful without ever appearing in your analytics.

Cite this:utm_source=chatgpt.com: how to see ChatGPT and other AI traffic in GA4.Len P. van der Hof. https://lenvanderhof.com/en/blog/see-ai-traffic-in-ga4/ · Published 14 October 2026.