What does utm_source=chatgpt.com mean?

It is a tracking parameter ChatGPT adds to links in its answers. When someone clicks through, your analytics records the session source as chatgpt.com. OpenAI says this lets publishers that allow OAI-SearchBot see ChatGPT referral traffic in tools like Google Analytics.

Should I remove utm_source=chatgpt.com from my URLs?

No. It does not change the page and it is how you know the visit came from ChatGPT. If the parameter creates duplicate URLs in your own systems, set a canonical tag on the page rather than stripping the tag.

Where do I find ChatGPT traffic in GA4?

Open Reports, Acquisition, Traffic acquisition, and look at the AI Assistant row in the default channel group, or switch the dimension to Session source and search for chatgpt.com.

Is Google AI Overviews traffic counted as AI traffic in GA4?

No. Google's default channel group puts clicks from AI Overviews and AI Mode in Organic Search, and the AI Assistant channel excludes them. Search Console also reports them inside the Web search type.

Why is my AI traffic so low if AI engines mention me?

Many people read the answer and do not click. Some clicks from mobile apps arrive without a referrer and land in Direct. Referral traffic undercounts AI visibility, so measure mentions in the answers too.

AI search glossary

AI referral traffic and utm_source=chatgpt.com in GA4

AI referral traffic is website visits that arrive from a link in an AI assistant or AI search answer, such as ChatGPT, Perplexity, Gemini, Copilot or Claude, identified in analytics by the referrer or by a tag like utm_source=chatgpt.com.

Also called: AI traffic, ChatGPT traffic, utm_source=chatgpt.com, LLM referral traffic

Why it matters for AI search

Referral traffic is the part of AI visibility you can see in your own analytics. It is also the smallest part: most AI answers that name you produce no click, and some app traffic arrives with no referrer. Use it to confirm that AI answers send real visitors, and pair it with direct measurement of mentions for the full picture.

What utm_source=chatgpt.com is

When ChatGPT links to a page in an answer, it adds a UTM parameter to the URL: ?utm_source=chatgpt.com. OpenAI's Publishers and Developers FAQ says ChatGPT includes utm_source=chatgpt.com in referral URLs so that publishers who allow OAI-SearchBot can track ChatGPT referral traffic in analytics tools such as Google Analytics.

That is all it is: a label. It does not mean the visitor is a bot, and it does not affect how the page is served or ranked. If you see it in your server logs or landing page reports, a person clicked a link in ChatGPT. To be linked in ChatGPT search at all, your site needs to allow OAI-SearchBot; OpenAI says sites opted out of it are not shown in ChatGPT search answers.

How to see AI referral traffic in GA4

Option 1: the AI Assistant channel. Google Analytics' default channel group now includes an AI Assistant channel, which Google describes as the channel for users arriving from sources like ChatGPT, Gemini, Deepseek, Copilot or Grok. Open Reports > Acquisition > Traffic acquisition and look for the AI Assistant row.

Option 2: filter by source. In the same report, change the primary dimension to Session source and search for chatgpt.com, perplexity.ai, gemini.google.com or copilot.microsoft.com.

Option 3: a custom channel group. For your own definition, go to Admin > Data display > Channel groups (Editor role needed), choose Create new channel group, add a channel such as "AI tools" with a condition on Session source matching the AI domains, and move it above Referral, since GA4 assigns traffic to the first channel that matches. Standard properties can have two custom channel groups, and Google says they apply to reports retroactively.

What it does not show

Google's AI features. Clicks from AI Overviews and AI Mode are counted in Organic Search, not AI Assistant. In Search Console they are part of the Performance report's Web search type.
Answers without a click. If ChatGPT names you and the reader buys later from a search, analytics credits the search. This is the zero-click gap.
Missing referrers. Some app clicks arrive without a referrer and show as Direct.

Example

Say a software company sees 300 monthly sessions with source chatgpt.com, converting at twice its site average. Separately, it asks ChatGPT its 30 main buyer prompts, five runs each, and is named in a fifth of answers. The traffic confirms value; the mention rate shows the size of the opportunity. Together they make the case for AI visibility work.

Questions

What does utm_source=chatgpt.com mean?: It is a tracking parameter ChatGPT adds to links in its answers. When someone clicks through, your analytics records the session source as chatgpt.com. OpenAI says this lets publishers that allow OAI-SearchBot see ChatGPT referral traffic in tools like Google Analytics.
Should I remove utm_source=chatgpt.com from my URLs?: No. It does not change the page and it is how you know the visit came from ChatGPT. If the parameter creates duplicate URLs in your own systems, set a canonical tag on the page rather than stripping the tag.
Where do I find ChatGPT traffic in GA4?: Open Reports, Acquisition, Traffic acquisition, and look at the AI Assistant row in the default channel group, or switch the dimension to Session source and search for chatgpt.com.
Is Google AI Overviews traffic counted as AI traffic in GA4?: No. Google's default channel group puts clicks from AI Overviews and AI Mode in Organic Search, and the AI Assistant channel excludes them. Search Console also reports them inside the Web search type.
Why is my AI traffic so low if AI engines mention me?: Many people read the answer and do not click. Some clicks from mobile apps arrive without a referrer and land in Direct. Referral traffic undercounts AI visibility, so measure mentions in the answers too.