What does utm_source=chatgpt.com mean in Google Analytics (GA4)?

It means the visitor clicked a link to your site inside ChatGPT. The tag sits in the page address and fills the source in Google Analytics, so you see chatgpt.com as the source. GA4 groups these visits in its AI Assistant channel, but some arrive without the tag or a referrer and are counted as Direct or Unassigned instead.

Facts

Google Analytics has an AI Assistant default channel for visits from sources like ChatGPT, Gemini, Deepseek, Copilot or Grok, checked on 2026-10-13. (Google Analytics Help: Default channel group)
That channel excludes Google's AI Overviews and AI Mode, which GA4 counts under Organic Search. (Google Analytics Help: Default channel group)
GA4 puts a visit in Direct when its source is (direct) and its medium is (not set) or (none), such as a saved link or a typed address. (Google Analytics Help: Default channel group)
Unassigned is the value GA4 uses when no other channel rule matches the visit's data. (Google Analytics Help: Default channel group)
Google says missing UTM parameters result in (not set) values in reports, and recommends always using utm_source, utm_medium and utm_campaign together. (Google Analytics Help: Collect campaign data with custom URLs)
In Google's Analytics Data API, the sessionSourceMedium dimension is the combined values of sessionSource, the source that initiated a session, and sessionMedium, the medium that initiated it, checked on 2026-10-13. (Google for Developers: Analytics Data API dimensions and metrics)
Matomo, another analytics tool, has two default campaign dimensions, name and keyword, and fills the campaign name from utm_campaign, utm_medium or utm_source, checked on 2026-10-13. (Matomo FAQ: Does Matomo support Google Analytics campaign parameters?)

Where does utm_source=chatgpt.com come from?

It comes from the link the visitor clicked in ChatGPT, not from your site. You did not add it, and you cannot remove it from ChatGPT's links. Google Analytics reads utm_source from the address and records chatgpt.com as the session source.

Why does ChatGPT traffic show as (not set) or Unassigned in GA4?

Because the tag carries a source but no medium. GA4 records the medium as (not set), and a visit whose source and medium match no channel rule ends in Unassigned. When GA4 instead matches the referrer to its list of AI assistants, it sets the medium to ai-assistant and the visit lands in the AI Assistant channel.

GA4 > Reports > Acquisition > Traffic acquisition
  Dimension: Session source / medium
  Search: chatgpt
  Secondary dimension: Landing page

Why does some ChatGPT traffic show up as Direct?

Because the visit arrived with neither the tag nor a referrer, so GA4 cannot tell where it came from. Common cases:

The person copied your address from the answer and pasted it into the browser
The link was opened from an app that sends no referrer
The person saw your name in the answer and typed your address later
Redirects on your site dropped the query string with the tag

Are AI Overviews clicks counted as ChatGPT-like AI traffic?

No. GA4 counts clicks from Google's AI Overviews and AI Mode as Organic Search, not AI Assistant. To see how your pages appear in Google's AI features, use Search Console, which reports them with the rest of Google Search.

How do I see which pages ChatGPT sends visitors to?

Open Traffic acquisition, filter the session source for chatgpt, then add Landing page as a secondary dimension. The result lists the pages people reached from ChatGPT. Read it as a minimum, since Direct hides part of the real number.

Step by step

Find the source. In GA4, open Reports, Acquisition, Traffic acquisition and switch the dimension to Session source / medium.
Filter for ChatGPT. Search for chatgpt to see every source / medium pair, including chatgpt.com / (not set).
Add the landing page. Add Landing page as a secondary dimension to see which pages ChatGPT sends people to.
Check your redirects. Ask your coding agent to confirm that redirects keep the query string, so the tag reaches the final page.
Watch the trend by page. Compare the same pages month by month, since the count is a floor, not the total.

Common mistakes

Reading only the AI Assistant channel and missing the chatgpt.com visits sitting in Unassigned.
Treating every Direct visit as non-AI traffic.
Stripping utm parameters in a redirect or a canonical rewrite, which erases the tag before GA4 sees it.
Expecting AI Overviews clicks in the AI Assistant channel; GA4 counts them as Organic Search.

How easyIndex solves it

easyIndex measures AI-assistant visitors per page on its own, by referrer and utm_source, so a chatgpt.com visit counts whatever channel GA4 gives it. The same dashboard shows which pages AI crawlers read and when, and Google indexing and searches from Search Console. Your coding agent installs the tracking, guided over MCP, and easyIndex checks it on the live site. US$ 30 per website a month, with a 7-day free trial.

Frequently asked questions

Can I see what the person asked ChatGPT?

No. The tag and the referrer say where the visitor came from, not the question they asked.

Should I add utm_medium myself?

You cannot change ChatGPT's links. You can build a GA4 custom channel group that treats source chatgpt.com as AI traffic.

Does GA4 also recognize Claude or Perplexity?

Google names ChatGPT, Gemini, Deepseek, Copilot and Grok as examples and does not publish the full list, so check your own source report.

Does a visit from ChatGPT mean ChatGPT recommends me?

It means ChatGPT showed a link to your page and someone clicked it. It does not say how often or for which questions.

Continue reading

Last verified on October 13, 2026.