How to See ChatGPT, Gemini and Perplexity Traffic in GA4

GA4 does not have an AI channel. Every visit from ChatGPT, Gemini, Claude, Perplexity or Copilot arrives as Referral and gets shuffled in with newsletter links, forum posts and everyone else who mentioned you. If you have been wondering whether AI assistants send you anything, the honest answer is that your Analytics has been hiding it in plain sight.

Here is how to get it back.

The 30-second version

Open Explore → Free form, set the dimension to Session source, add Sessions as the metric, then apply this filter:

Session source  matches regex
chatgpt|openai|perplexity|gemini|claude|anthropic|copilot

That single regex covers every mainstream assistant currently sending referral traffic. Everything below is the detail — why those specific strings, what the numbers mean, and where they lie to you.

Which hostnames actually arrive

Assistants do not send a tidy ai_assistant parameter. They send an ordinary HTTP referrer, and the hostname varies by product and by surface:

Assistant	Hostnames seen in sessionSource	Match on
ChatGPT	chatgpt.com, chat.openai.com	chatgpt, openai
Gemini	gemini.google.com	gemini
Claude	claude.ai	claude, anthropic
Perplexity	perplexity.ai, www.perplexity.ai	perplexity
Copilot	copilot.microsoft.com, bing.com/chat	copilot

Two things worth noticing. ChatGPT migrated from chat.openai.com to chatgpt.com, so a filter written before the move silently under-counts — matching both substrings is not belt-and-braces, it is required for any lookback window that spans the change. And Copilot traffic can arrive as a bing.com path rather than a distinct host, which is why a naive Source = copilot.microsoft.com exact match misses a chunk of it.

Making it permanent: a custom channel group

An exploration answers the question once. A channel group answers it every time you open a report.

1. Admin → Data display → Channel groups
2. Open the default group and choose Copy
3. Add a new channel — call it AI assistants — and drag it above Referral
4. Condition: Source matches regex chatgpt|openai|perplexity|gemini|claude|anthropic|copilot
5. Save

Order matters. Channel groups evaluate top-down and stop at the first match, so a rule placed below Referral will never fire.

A custom channel group changes how sessions are grouped in reports, not how they were collected. It will not repair rows already exported to BigQuery under the old grouping, and it does not apply to the Realtime report.

The number is a floor, not a total

This is the part most write-ups skip, and it is the part that will make you distrust your own dashboard if nobody tells you.

Three separate leaks sit between “an assistant cited you” and “GA4 recorded a session”:

• Citations that never get clicked. The assistant answers the question in the chat. You were the source, you got no session. This is the largest gap and it is invisible from inside Analytics.
• Stripped referrers. Some assistant surfaces and in-app browsers do not pass a referrer at all. Those sessions land in Direct, indistinguishable from someone typing your URL.
• The first-hop problem. A user who opens a link, then navigates before the tag fires, can be attributed to the internal page rather than the assistant.

So when the number comes back smaller than you hoped, the correct reading is not “AI sends no traffic”. It is “AI sends at least this much traffic, plus an unknown amount that is unmeasurable from here.”

What to do with the number

Once you can see it, the useful move is to cross it with your landing pages. AI assistants cite specific pages, not domains. If three of your forty pages account for most assistant referrals, those three pages are the ones models find quotable — clear structure, direct answers, real numbers — and the other thirty-seven are the ones to rewrite.

That is the whole loop: see which pages get cited, work out what those pages do differently, do more of it.

We got tired of rebuilding this exploration

Every time we wanted this number, it was the same four minutes: new exploration, remember the regex, apply it, read it, close it, lose it. So we built it into a tab.

GA4 Simple View does the same regex match against sessionSource, normalises the hostname variants into one name per assistant (chatgpt.com and chat.openai.com both become ChatGPT), and puts the breakdown on the Insights tab next to everything else. Same data, same API, no exploration to rebuild.

The manual method above works perfectly well and costs nothing. Use it. If you find yourself running it weekly, that is when a shortcut starts paying for itself.