What counts as AI referral traffic
AI referral traffic is a visit in which a person asked an AI assistant a question, got an answer with links and clicked one of them. The sources are ChatGPT (including its search), Perplexity, Gemini, Microsoft Copilot, Claude and DeepSeek.
Visits made by software do not belong here: an AI agent opening pages on a user’s behalf produces AI agent traffic, and bots that fetch pages for model training and indexing are AI crawlers. Google AI Overviews and AI Mode are a special case: they are AI answers, but analytics records their clicks as organic traffic from Google.
How to recognise it: referrer and UTM
| Source | Signal in analytics | Note |
|---|---|---|
| ChatGPT | referrer chatgpt.com, parameter utm_source=chatgpt.com | ChatGPT adds the parameter itself, so the visit is visible even without a referrer |
| Perplexity | referrer perplexity.ai | usually passes a referrer |
| Gemini | referrer gemini.google.com | usually passes a referrer |
| Claude | referrer claude.ai | usually passes a referrer |
| Microsoft Copilot | referrer copilot.microsoft.com | practitioners report the referrer is often lost |
| AI Overviews, AI Mode | google.com | in Search Console, part of the overall Web search type |
As of September 2026, the GA4 default channel group includes an AI Assistant channel: sessions from recognised assistants get the medium ai-assistant. In other analytics tools, clicks are collected with a segment by referring domain and UTM parameters.
Measurement blind spots
- No referrer. Mobile apps and some chat interfaces open links without a Referer header, and the visit falls into direct traffic.
- The platform builds the link. You cannot add your own UTM parameter to a link inside an assistant’s answer: you only see what the platform passes on.
- Google’s AI answers. Clicks from AI Overviews and AI Mode cannot be isolated.
- Delayed purchases. A person discovers the store in an assistant’s answer and buys a week later via search or a direct visit. A last-click report will not show the assistant at all.
Important: public estimates of how well AI traffic converts vary widely between studies. Do not apply other people’s numbers to your store — measure your own funnel for the segment.
What an online store should do
- Build a segment or channel group: the assistants’ domains plus utm_source=chatgpt.com. Review the list every quarter — services change domains and link behaviour.
- Look at landing pages: they show which content assistants cite and tie directly to your AI citability.
- Measure the segment’s funnel separately: conversion rate, average order value, share of new customers, pages per session.
- Check attribution: beyond the last click, look at assisted conversions where the assistant was one of the touchpoints.
- Watch direct visits to product pages and articles: unexplained growth there often means AI clicks that arrived without a referrer.