How to see AI traffic in Google Analytics 4

Where GA4 already shows AI traffic

• Go to Reports > Acquisition > Traffic acquisition. The table's first dimension is Session default channel group.
• Read the AI Assistant row. That is GA4's own channel for assistants; Google sets the medium to ai-assistant when the referrer matches its list.
• Change the dimension to Session source / medium to see which assistants are in it, one row each.
• Clicks from Google's AI Overviews and AI Mode are not in this row. Google counts them in Organic Search, together with ordinary search clicks.

Where AI visits land instead

The AI Assistant rule reads the referrer. Three kinds of AI visit do not give it one it can match, and each ends up somewhere else.

• Tagged, with no referrer: look under Unassigned. ChatGPT adds utm_source=chatgpt.com to its links, and its iPhone app sends no referrer. Google says that when any UTM parameter is on the URL, GA4 takes the traffic source from the UTM parameters, and that missing UTM parameters show as (not set). OpenAI's page names only utm_source, so where the link carries no utm_medium the visit has source chatgpt.com and medium (not set), which matches neither the AI Assistant, Referral nor Direct rule; Unassigned is GA4's value when no channel rule matches. Google's pages do not describe this case by name, so check your own Session source / medium list for chatgpt.com / (not set).
• An assistant missing from Google's list: look under Referral. Google names examples and does not publish the full list. A referral from an assistant that is not on it keeps the medium referral, and Referral is the channel for that medium.
• No referrer and no tag: it is Direct. GA4's Direct rule is source (direct) with no medium, which is what a visit with neither signal looks like. Nothing in GA4 can recover it, because nothing was sent.

How much of your AI traffic falls into the first group depends on your audience. On promvia.app it was most of it: of the 24 ChatGPT visits our snippet recorded between 25 August and 19 October 2026, 22 arrived with no referrer and only the utm_source tag. We do not have GA4 on the production site, so this is what our own tracking saw, not a count of what GA4 did with those visits. Google's pages also do not say which wins when a visit carries both an AI referrer and a utm_source tag; the source is chatgpt.com either way, which is why the fix below matches the source.

The fix: a custom channel group that matches the source

A channel defined by Source catches the referral and the tagged visit alike: in GA4 a referral's source is the referring hostname, and a tagged visit's source is the utm_source value. It does not depend on the medium, so (not set) does not matter.

• In Admin, under Data display, open Channel groups and click Create new channel group. It starts as a copy of the default group. You need the Editor role or above on the property, and a standard property can have two custom groups.
• Click Add new channel, name it AI assistants, and add the condition Source matches regex.
• Paste this pattern, built from the sources Promvia's classifier matches: ^(www\.)?(chatgpt\.com|chat\.openai\.com|chatgpt|perplexity\.ai|perplexity|gemini\.google\.com|gemini|copilot\.microsoft\.com|copilot|claude\.ai|claude)$ — add a source when an assistant you care about is missing.
• Click Reorder and move AI assistants above Referral, as Google advises. Traffic goes into the first channel it matches, so below Referral the assistants' referrals would stay in Referral.
• Save, then pick the group as the dimension in Traffic acquisition. Google says custom channel groups apply to reports retroactively, so the past months fill in too.

What GA4 still cannot show

• Visits with no signal. Our August click-through test found Claude on desktop and the Claude and Gemini iPhone apps sending neither a referrer nor a tag; those visits are Direct in GA4 and in every other tool. Why AI traffic shows up as Direct has the measurement.
• Google's own AI answers, apart from search. AI Overviews and AI Mode clicks are inside Organic Search.
• Which visit led to which order. GA4 reports revenue by its own attribution model. Joining one visitor's ChatGPT visit to that visitor's order is a different measurement, described in how to measure revenue from ChatGPT referrals.

Promvia can read your GA4 numbers for you with read-only access: sessions, key events and purchase revenue per day for each AI source, filtered by session source, so tagged visits are included whatever channel GA4 put them in. It reads GA4's totals, not individual visits, and it is on every plan, the free one included. The wider picture, including crawler logs, is in how to track AI traffic to your website.

Frequently asked questions