How to check whether ChatGPT and Perplexity know your brand, and how to track AI referral traffic in GA4 once you know.
Checking whether AI systems know a brand starts with manual testing: running the actual questions a buyer would ask, category questions, comparison questions, "who does X" questions, directly into ChatGPT, Perplexity, Google AI Overviews, and Microsoft Copilot, and recording whether the brand is mentioned, how it's characterized, and which competitors appear instead. This manual audit is the necessary first step, since standard rank trackers don't see AI citations at all.
A workable starting process:
Once a brand knows it's being cited somewhere, the next question is whether that citation actually sends visitors, and GA4 needs deliberate setup to answer this, since it doesn't track this cleanly by default.
The native option. Google added a built-in "AI Assistant" channel to GA4's Default Channel Group on May 13, 2026. When an incoming session's referrer matches a recognized AI domain, GA4 now automatically tags it with the medium ai-assistant and files it under this channel, no setup required. Find it under Reports → Acquisition → Traffic acquisition, with the primary dimension set to Session default channel group.
Its limits. This native channel has real gaps. Google's documentation names sources like ChatGPT, Gemini, DeepSeek, Copilot, and Grok, but Perplexity is not listed, and clicks from Google AI Overviews and AI Mode are bundled into Organic Search rather than broken out separately. Traffic from native mobile apps or privacy-restricted contexts often carries no referrer header at all, landing silently in Direct traffic, meaning the true AI referral number is very likely higher than what any channel report shows.
Building a custom channel group. For full coverage, including Perplexity: go to Admin → Data display → Channel groups, copy the Default Channel Group, and add a rule with Session source matching a regex pattern covering the AI domains that matter, for example a pattern including chatgpt.com, perplexity.ai, claude.ai, gemini.google.com, and copilot.microsoft.com. This custom rule needs to sit above the built-in Referral rule in the channel order, or GA4 will file matching sessions under generic Referral before ever checking the AI rule.
Once conversions or key events are properly configured in GA4, this setup makes it possible to see, per AI source, how many sessions, conversions, and how much revenue or lead value are attributable to AI referral traffic specifically, the evidence needed to justify continued investment in AI search optimization to anyone who needs a number, not just a citation screenshot.
This is part of AI Search & SEO and Analytics & Data. This diagnosis process is exactly what's covered in AI visibility: from invisible to citable.
Want help setting this up properly, or interpreting what the data is actually telling you? Get in touch.