How to track ChatGPT and AI referral traffic in GA4

The short answer. Create a custom channel group in GA4 with a channel called “AI assistants” that matches the session source against the hostnames of the assistants, and put it above Referral. Custom channel groups apply to past data, so you see the history straight away. Expect an undercount: some AI clicks arrive with no referrer and land in Direct, and AI Overviews clicks are indistinguishable from other Google traffic.

Step by step

1. Open channel groups. In GA4, go to Admin → Data display → Channel groups. You need Editor access or above on the property.
2. Copy the default group. Click Create new channel group. GA4 starts it as a copy of the default group, so every existing channel stays. Name it something like “Channels with AI”.
3. Add the AI channel. Click Add new channel, name it “AI assistants”, add a condition on Source, choose matches regex, and paste the regex below. Save the channel. GA4 won’t let you rename a channel later, so pick the name now.
4. Move it above Referral. GA4 puts a visit in the first channel whose rules it matches. Click Reorder, drag “AI assistants” above “Referral”, apply, and save the group.
5. Read it. Open Reports → Acquisition → Traffic acquisition and switch the primary dimension from the default channel group to yours.

The regex

This is the same pattern Mentioned uses to count AI visits when you connect GA4. It matches the hostname with or without www. or another subdomain:

^(.+\.)?(chatgpt\.com|chat\.openai\.com|perplexity\.ai|gemini\.google\.com|bard\.google\.com|claude\.ai|copilot\.microsoft\.com|you\.com|phind\.com|meta\.ai|chat\.deepseek\.com|grok\.com|poe\.com)$

It covers the referrer hostname and the utm_source=chatgpt.com tag ChatGPT adds to many of its links, since GA4 reads both as the session source. Add hosts as new assistants appear.

Quicker: an exploration

If you only need a number today, go to Explore → Free form, add Session source as a dimension and Sessions and Key events as metrics, and filter Session source with the same regex. It doesn’t change your reports, and it doesn’t use one of your custom channel groups, of which Google allows two on a standard property.

What GA4 can’t show you

• Clicks with no referrer. A link copied out of an answer into a new tab, or opened from some apps, can arrive with no referrer and no UTM tag. GA4 files it as Direct. Seer Interactive’s testing in June 2025 found ChatGPT tags many cited sources, but not every one.
• AI Overviews and AI Mode. These clicks arrive as google / organic. Google says AI features are counted in Search Console’s Performance report under the Web search type, mixed in with the rest of Search.
• Recommendations that never become a click. A buyer who reads “the usual shortlist is A, B and C” and then searches for B by name shows up as branded search or direct traffic, if at all. This is the biggest gap, and no analytics tool closes it.

So AI referral traffic is a lagging, partial signal. It tells you some recommendations turn into visits. It can’t tell you how often you’re recommended, for which questions, or who’s named instead.

Put the two side by side

The useful view is both at once: what the assistants say about you, and whether those answers turn into visits. Mentioned does that. It asks ChatGPT, Claude and Gemini your buyers’ questions the same way every week, and when you connect Search Console and GA4, read-only, its Search & traffic screen shows your top queries and your AI-referred sessions next to your AI visibility. The data is fetched from Google when you open the page and isn’t stored.

For what to do when the numbers are low, start with how to get mentioned by ChatGPT and Claude.

Questions

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