How to track ChatGPT and AI traffic in GA4

TL;DR GA4 now has an AI Assistant channel in its default channel group: sessions referred by assistants on Google's list, such as ChatGPT, Gemini and Copilot, get the medium ai-assistant and their own row in acquisition reports. Three things it does not cover: assistants missing from Google's list, which stay in Referral; AI visits without a referrer, which land in Direct; and Google's AI Overviews and AI Mode, which count as Organic Search. A custom channel closes the first gap; the other two you report as a known floor.

AI assistants are a new source of visits, and SEO teams are asked to report on them. GA4 has caught up in part: it recognises the main assistants on its own. The rest of the work is knowing what the channel leaves out, and noticing when a tracking change makes AI traffic disappear.

The AI Assistant channel in GA4

Google's default channel group defines AI Assistant as traffic from sources "like ChatGPT, Gemini, Deepseek, Copilot, or Grok". The rule works on the referrer: when it matches Google's list of AI assistants, GA4 sets the medium to ai-assistant and the campaign to (ai-assistant), and the session goes to the AI Assistant channel. A visit you tag yourself with utm_medium=ai-assistant lands there too.

To see it, open Reports > Acquisition > Traffic acquisition with Session primary channel group as the dimension and look for the AI Assistant row. Switch the dimension to Session source / medium to see which assistants send the visits.

Two things to know before you report on it:

• Check older months. AI visits from before the channel reached your property can still sit in Referral. When you compare periods, add the AI referrers in Referral for the earlier months, or the trend will show a jump that is only a relabel.
• Google does not publish the full list. Its examples do not include Perplexity or Claude. If those send you traffic, check where it lands.

Find the assistants the channel misses

1. In Traffic acquisition, set the dimension to Session source / medium.
2. Search for perplexity, claude, chatgpt, gemini, copilot and any assistant your audience uses.
3. Anything with the medium referral instead of ai-assistant is AI traffic the default channel does not count.

If you find some, a custom channel group puts them together with the rest.

Add the missing assistants with a custom channel

A custom channel group keeps the default definitions and adds what you need. It applies to every report that uses channels, including conversions.

1. Go to Admin > Data display > Channel groups.

2. Copy the Default channel group and name the copy, for example Default + AI.

3. Edit the AI Assistant channel, or add a new one, with two conditions joined by OR:

   • Default channel group · exactly matches · AI Assistant
   • Session source · matches regex · a pattern with the missing domains, for example:

   ^(.*\.)?(perplexity\.ai|claude\.ai)$
   

4. Check the order: the channel must sit above Referral. GA4 assigns each session to the first channel whose conditions match; below Referral, it never gets the extra sources.

5. Save, then select the new group in the Traffic acquisition report.

Custom channel groups also apply to past data, which helps with the relabel problem above: add the domains of the assistants you had before the default channel existed, and the history lines up. Review the list every few months, because new assistants appear. How channel groups work, and why order matters, is covered in our guide to GA4 channel groups.

Build an exploration for landing pages

Channels tell you how much traffic. An exploration tells you where it lands, which is what an SEO or content team acts on.

1. Open Explore > Free form.
2. Add the dimensions Session source, Session medium and Landing page + query string, and the metrics Sessions, Engaged sessions and Key events.
3. Add a filter: Session medium · exactly matches · ai-assistant, or use your custom channel group as the filter if you built one.
4. Put Landing page in rows and Session source in columns.

The result is the list of pages AI assistants send people to, by assistant. It is usually short and different from your top organic pages, which is useful in itself.

What GA4 cannot see

Every AI traffic number in GA4 is a floor, not a total.

• Visits without a referrer land in Direct and stay there. A visitor who reads an answer in a mobile app and types your URL looks exactly like someone who typed it from memory. A rise in Direct sessions on deep pages, not just the home, is often the sign.
• Google's AI Overviews and AI Mode count as Organic Search. GA4 cannot separate them from clicks on regular results.
• Visitors who decline analytics consent are not in GA4 at all, whatever the source.
• Answers without a click are not traffic. An assistant can cite your page and send nobody; analytics only sees the visits.

So report AI traffic as a trend from a known floor, and say so in the report.

Keep the numbers honest

AI traffic is small on most sites, which makes it fragile: a change that would be a rounding error elsewhere wipes it out.

• A redirect or a single-page app that drops the referrer moves AI visits into Direct overnight.
• A consent change cuts every source at once, AI included.
• Internal links with utm_ parameters overwrite the source of the session, so a visitor from ChatGPT who clicks one becomes a campaign visitor.
• A release that removes the GA4 tag from a template makes the pages AI assistants link to most stop reporting.

Trackingplan reads these sources where they are collected. Its acquisition view lists your referrers, sources and landing pages from the hits your site sends, independent of how GA4 groups them, and you can set a warning on a referrer such as chatgpt.com or on a landing page, so a drop shows up the day it happens. How to read that view is in the Acquisition docs. The classification into channels stays in GA4.

The channel is there by default now. Keeping its numbers accurate is the ongoing part, and it depends on the same thing every other report depends on: tracking that works.

Frequently asked questions

Can GA4 track traffic from ChatGPT?

Yes, when the visit carries a referrer or a utm_source. GA4's default channel group has an AI Assistant channel: when the referrer matches an assistant on Google's list, such as ChatGPT, GA4 sets the medium to ai-assistant and files the session under that channel. Visits that arrive without a referrer land in Direct.

Which AI assistants does GA4's AI Assistant channel include?

Google names ChatGPT, Gemini, Deepseek, Copilot and Grok as examples but does not publish the full list of referrers. Assistants that are not on the list stay in Referral, so check your session sources for the ones you care about, such as Perplexity or Claude.

How do I add Perplexity or Claude to AI traffic in GA4?

Create a custom channel group: copy the default group, add a channel whose conditions are default channel group exactly matches AI Assistant, or session source matches a regular expression of the missing domains, and move it above Referral, because GA4 assigns each session to the first channel that matches.

Can I see traffic from Google AI Overviews in GA4?

Not separately. Google counts clicks from AI Overviews and AI Mode as Organic Search, so they arrive as google / organic, the same as a click on a regular result.