How to track ChatGPT and Perplexity traffic in GA4

ChatGPT traffic shows up as referral traffic with the source chatgpt.com (older visits may show chat.openai.com). Perplexity shows as perplexity.ai, Gemini as gemini.google.com, Microsoft Copilot as copilot.microsoft.com and Claude as claude.ai. Since May 2026, GA4's default channel group has an AI Assistant channel: sessions from assistants Google recognizes get the medium ai-assistant and land there. Google hasn't published which assistants it recognizes, so check your report: sources missing from that row still land in Referral, next to every blog and partner that links to you (Google Analytics Help).

Open Reports → Acquisition → Traffic acquisition and look for the AI Assistant row. Then change the primary dimension to Session source / medium and type perplexity or copilot in the search box to find assistants that row doesn't cover. This works for a quick look, but it's one engine at a time and not saved. For ongoing reporting, build a channel group.

A custom channel group gives every AI assistant, recognized or not, one row in every acquisition report, including past data (Google Analytics Help). You need the Editor role.

1. Go to Admin → Data display → Channel groups.
2. Copy the Default channel group so you keep all standard channels, and name the copy "Channels with AI".
3. Click Add new channel and name it AI assistants.
4. Set the condition: Source · matches regex · paste the regex below.
5. Save the channel, then use Reorder to move AI assistants above Referral. GA4 assigns each session to the first channel that matches, so if Referral comes first, it takes the AI traffic.
6. Save the group. In Traffic acquisition, switch the dimension to your new channel group.

Regex for the source condition:

.*(chatgpt\.com|chat\.openai\.com|perplexity\.ai|gemini\.google\.com|bard\.google\.com|copilot\.microsoft\.com|claude\.ai|grok\.com|chat\.deepseek\.com|chat\.mistral\.ai).*

Add new domains as assistants launch. Keep the list in one shared document so every property uses the same definition.

GA4 sees clicks with a referrer or a UTM tag. It misses three kinds of AI influence:

• Visits without a referrer. Some apps and in-app browsers strip the referrer, so the visit lands in Direct.
• Google's AI features. Clicks from AI Overviews and AI Mode are reported as Google organic search, not as a separate source (Google Search Central).
• Answers with no click. Most of the value of an AI recommendation happens before the click: the buyer reads the answer, remembers your name, and searches for you later. That shows up as branded search or direct traffic, if at all.

That's why AI traffic is an outcome metric, not a visibility metric. Read it next to mention rate and share of voice; our guide to AI visibility metrics explains them.

Three views answer most questions:

1. AI sessions over time: the AI assistants channel, weekly. Is it growing?
2. Landing pages from AI: which pages AI users land on. These are the pages engines cite; keep them current.
3. Conversions by channel: key events from AI assistants against organic and paid. AI visitors often arrive with a shortlist already made, so compare conversion rates.

In explorations, add Session source as a breakdown to see which assistant drives each page.

Match the landing pages from your AI channel with the pages engines cite for your prompts. If a page is cited often but gets few visits, the answer may already satisfy the question; add a reason to click, such as a calculator, data or pricing. If a page gets AI visits but isn't cited for your key prompts, it's being found for other questions; check which with citation tracking.

GA4's AI Assistant channel catches the assistants Google recognizes. To catch the rest, copy the default channel group, add an "AI assistants" channel with the regex above, move it above Referral, and report it weekly. Remember what GA4 can't see, and track AI mentions alongside the clicks.