If you have started seeing `utm_source=chatgpt.com` in URLs in Google Analytics, you are not alone. It means someone clicked a link in ChatGPT and came to your site. In this article we explain where to find this traffic in Google Analytics 4 (GA4), what Google's new "AI Assistant" channel counts, and what this number does not show.
What does utm_source=chatgpt.com mean?
OpenAI's FAQ page for publishers says it clearly: ChatGPT automatically adds the `utm_source=chatgpt.com` parameter to the URLs it refers people to. The goal is to let analytics tools track traffic from ChatGPT search results separately.
The same page also sets a condition: this tracking is described for publishers that allow OAI-SearchBot to access their site. OAI-SearchBot is the bot ChatGPT uses to show sites in its search answers. According to OpenAI, you should not block this bot if you want your content to appear in summaries and citations in ChatGPT. We cover this in more detail in Why doesn't ChatGPT recommend my brand.
What is the AI Assistant channel in GA4?
On May 13, 2026, Google added a new channel to GA4 for traffic from AI assistants. According to Google Analytics' what's new page, three things changed:
- If the referring site is a recognized AI assistant, the medium value is automatically set to "ai-assistant".
- These visits are grouped under the "AI Assistant" channel in the Default Channel Group.
- The campaign name appears as "(ai-assistant)".
Google's default channel group documentation defines this channel as visits from sources such as ChatGPT, Gemini, Deepseek, Copilot or Grok. The what's new page also names Claude as an example.
The same documentation makes an important distinction: Google's own AI Overviews and AI Mode are not part of this channel. Clicks from them are counted in the Organic Search channel.
Step by step: where do you find ChatGPT traffic?
No setup is needed. The channel works automatically. Follow this path:
- Open the Reports section in GA4.
- Under Acquisition, go to the Traffic acquisition report.
- Make sure Session default channel group is selected as the table's primary dimension. Look for the "AI Assistant" row in the list.
- To see which assistant the visits came from, switch the dimension to Session source / medium and type "chatgpt" in the table search.
In this row you will see the number of sessions, engagement time and any conversions. This is usually the most valuable information: how long do these visitors stay, which page do they land on, do they fill in a form?
Check which pages they land on
Once you find the channel row, add landing page as a secondary dimension. This gives you an indirect hint about which pages on your site ChatGPT cites as sources.
On most sites a few pages stand out. Note these pages. Are they up to date, accurate, and do they lead the visitor to the next step? A visitor from AI usually arrives with a specific question. If the page does not answer that question, the visit is short.
Where is traffic from Google AI Overviews and AI Mode?
These two features are part of Google Search, so they do not appear in a separate channel. According to Google's AI features documentation, sites that appear in AI Overviews and AI Mode are counted in the overall search traffic in the Performance report in Search Console, under the "Web" search type.
So in GA4 these clicks sit in the Organic Search channel, and in Search Console they sit with regular search clicks. Google's documentation does not mention a report that shows these clicks in a separate row. Knowing this matters when you read the number in the AI Assistant channel: that number does not include clicks from Google's own AI features.
What about Perplexity and other assistants?
Perplexity is not named in the examples in Google's documentation. The documentation only gives examples, not a full list. So check which channel Perplexity traffic falls into in your own account: search for "perplexity" in the source/medium report and see which channel group the row appears in.
The same check applies to other new assistants. The list may change over time.
What does this number not show?
GA4 only counts clicks. Most AI visibility, however, happens without a click.
A buyer asks ChatGPT, "Recommend accounting software in Istanbul." Your brand appears in the answer. The buyer notes your name and, a few days later, comes to your site by searching for your brand on Google or typing your address. This visit does not appear in the AI Assistant channel. It is recorded as a brand search or as direct traffic.
The channel rule itself also sets a limit. According to Google's documentation, the medium gets the "ai-assistant" value only when the referring site is a recognized assistant. Visits that arrive without referrer information do not fall into this channel.
Think about it the other way too. If the answer names your competitor and not you, you see no trace in GA4. The lost buyer does not appear in the report.
So GA4 data alone does not answer the question "how visible are we in AI?" It only answers "how many people clicked through from AI?"
Read the two measures together
For the full picture you need two separate measures:
- Visibility: in the questions your buyers ask, how often do ChatGPT, Gemini and Perplexity mention your brand, and who do they mention instead?
- Clicks: how many people come to your site from the answers that mention you, and what do they do?
GA4 cannot give you the first one. For that, you need to ask the engines the questions on a regular basis. We explained how in How to measure AI visibility.
AIShortlist does this first measurement. It suggests buyer questions from your site, and once you approve them, it asks the questions to the three engines separately. On paid plans the measurement repeats every week. If your visibility score rises while the AI Assistant channel in GA4 also grows, the two measures point in the same direction.
A note for agencies
For agencies that prepare reports for clients, these two measures make sense in the same presentation. Clicks and conversions come from GA4, visibility and competitor position come from AIShortlist. On AIShortlist's Pro plan, agencies can share the report with their own logo.
In short
`utm_source=chatgpt.com` shows that someone clicked through from ChatGPT. GA4's AI Assistant channel collects these visits on its own. But clicks are only a small part of visibility. To see answers where you are mentioned but not clicked, or where you are not mentioned at all, you need to ask the engines the questions regularly.
If you want to see which questions you are mentioned in today, you can run a 10-question measurement with the free trial. The trial includes 1 brand and 1 measurement, and no card is required.