AI Traffic Attribution: How to Track ChatGPT, Gemini and AI Overviews Visits

AI traffic attribution is the process of identifying website visits that start in an AI tool, such as ChatGPT, Gemini, Perplexity, Claude or Copilot, and crediting them to that source instead of to Direct or Referral. In Google Analytics 4 (GA4), start with the built-in AI Assistant channel in Reports > Acquisition > Traffic acquisition, then add a custom channel group with a source regex to catch assistants the default list misses.

Checked against Google Analytics Help, Google Search Central, Search Console Help, MDN Web Docs and the crawler documentation from OpenAI, Perplexity and Anthropic on October 20, 2026.

Three kinds of AI visits behave differently in your reports. Clicks from chat assistants usually carry a referrer and land in the AI Assistant channel. Clicks from Google's AI Overviews and AI Mode land in Organic Search. Some AI visits arrive with no source at all and are counted as Direct. Good attribution handles all three.

Where AI visits show up in GA4 today

GA4's AI Assistant channel: what it covers

Google's default channel group documentation describes AI Assistant as "the channel by which users arrive at your site from sources like ChatGPT, Gemini, Deepseek, Copilot, or Grok." It also states that the channel "excludes Google's AI Overviews and AI Mode."

The rule behind it is simple. When the referrer matches Google's internal list of AI assistants, GA4 sets the medium to ai-assistant and the campaign to (ai-assistant). The channel then collects every session whose medium exactly matches ai-assistant. Google does not publish the full list of assistants, so you cannot see in advance which tools it covers.

What this means in practice:

• You do not need to build anything to see the main assistants. Open the Traffic acquisition report and look for the AI Assistant row.
• An assistant that is not on Google's list falls through to another channel, usually Referral.
• You cannot edit the default channel group. Google keeps it as a universal reference, so additions go into a custom channel group.

How to see AI assistant referrals in GA4

1. Sign in to Google Analytics and select Reports in the left menu.
2. Select Acquisition > Traffic acquisition. If the report is missing, an Editor can add it back to the left navigation.
3. Keep Session default channel grouping as the dimension and find the AI Assistant row.
4. Change the dimension to Session source (or Session source / medium) to see each assistant separately, for example a source of chatgpt.com with a medium of ai-assistant.
5. Add a comparison or filter for Session default channel grouping exactly matching AI Assistant, then add Landing page as a secondary dimension to see which pages AI tools send people to.
6. Compare engaged sessions, engagement rate, key events and revenue against Organic Search for the same date range.

How to build a custom AI channel group (with regex)

A custom channel group lets you add assistants Google's list misses and keep one "AI assistants" line in every report. Google's own help page walks through this exact use case.

1. Go to Admin, and under Data display, click Channel groups. You need the Editor role or above on the property.
2. Click Create new channel group. This starts with a copy of the default group, including the AI Assistant channel.
3. Name the group, for example "Channels with AI."
4. Click Add new channel and name it "AI assistants (all)."
5. Add a condition on Source, choose matches regex, and paste the regex below.
6. Click Reorder and drag the new channel above Referral. GA4 puts each session in the first channel it matches, so order matters.
7. Click Save channel, then Apply, then Save group.

Use this regex for the Source condition:

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

How it works: GA4 regex is a full match and case sensitive by default, so the pattern is anchored with ^ and $. The optional (.*\.)? at the start catches subdomains such as www.perplexity.ai and www.meta.ai. Each dot is escaped so it only matches a real period.

Google's help page offers a broader example regex that includes patterns such as .*gpt.* and ^.*ai. Those catch more assistants, but they can also match unrelated sources that happen to contain "ai" or "gpt" in their names. A named list is easier to audit. Add a new hostname whenever you spot an AI tool in your Referral or Unassigned rows.

Custom channel groups apply to your reports retroactively. A standard GA4 property can have 2 custom channel groups (5 on Analytics 360), each with up to 50 channels. Custom channel groups are not available in the BigQuery export schema.

AI assistant hostnames in the regex

Each hostname below was checked on October 20, 2026 by loading the address or confirming it from the vendor's own website.

Two cautions. First, a link inside a chat can carry its own UTM tag. GA4 stores a utm_source value as the source, so a tagged link shows the tag's value instead of the referrer. The regex above still matches when that value is the same hostname, but check your source list for other spellings. Second, mobile apps for these tools may not send a referrer at all, which is the next problem.

Why some AI visits arrive as Direct

An older explanation says AI tools strip referrers because they run over HTTPS. That is not how browsers work. MDN Web Docs states that the default referrer policy, strict-origin-when-cross-origin, sends the origin for cross-origin requests when the protocol stays the same, which covers HTTPS to HTTPS. A click from https://chatgpt.com to your HTTPS site normally carries chatgpt.com as its origin.

The real reasons a referrer goes missing:

• rel="noreferrer" links. MDN describes this attribute as telling the browser to omit the Referer header entirely.
• A strict referrer policy. A site can set no-referrer for all outgoing links.
• Apps and in-app browsers. A click inside a mobile or desktop app can open your site without a referring web page.
• Redirects and link shorteners. Google's help page on (direct) / (none) traffic says redirects, including HTTPS to HTTP redirects, can strip UTM parameters, and URL shorteners can strip referral details.
• Ad blockers. The same page notes that ad blockers can interfere with the cookies used to identify where traffic came from.
• Copy and paste. A reader who copies a URL out of a chat answer and pastes it into a new tab is a Direct visit by definition.

This is why "non-attributed traffic" matters. GA4 uses the source (direct) with medium (none) for traffic without a clear referral source. Some AI visits will always sit there. You can reduce the share, but not remove it.

Google AI Overviews and AI Mode count as Organic Search

GA4's channel documentation describes Organic Search as non-ad links in organic search results, "including Google's AI Overviews and AI Mode." So if a reader clicks your link inside an AI Overview, GA4 records it as Google organic traffic, the same as a blue link. GA4 alone cannot separate the two.

Older guides use the name "SGE" for this feature. Google's documentation now calls the features AI Overviews and AI Mode.

What Search Console reports about AI features

Search Console is the only Google-side view of AI Overviews and AI Mode, and it changed in 2026.

• Performance report. Google's AI features guide says appearances in AI features are included in the overall Performance report under the Web search type. They are mixed with other results, not split out.
• How they are counted. Search Console Help says clicking a link to an external page in an AI Overview counts as a click. An AI Overview occupies a single position, and all its links get that same position. In AI Mode, a follow-up question counts as a new query.
• Generative AI performance report. Google announced dedicated generative AI performance reports on June 3, 2026, and states that as of August 31, 2026 they have rolled out to all websites worldwide. The Search report covers AI Overviews and AI Mode.
• What it shows. Impressions only, by page, country, device and date, with a filter for text-based or multimodal web searches. The help page defines impressions as how many times links to your site were shown in a generative AI feature on Google Search. Google's announcement says more metrics may be added over time.
• When it is empty. Search Console Help says the report may not appear if your site has not received enough impressions in generative AI features, or if you have excluded your site from them.

Put together: Search Console tells you how often Google's AI features showed your pages. GA4 tells you what those visitors did, but only as part of Organic Search. Watch the two side by side for the pages that gain AI impressions.

AI crawlers and agents: a separate signal in server logs

Not every AI "visit" is a person. AI companies fetch pages with named user agents, and GA4 does not count them, because Google Analytics automatically excludes traffic from known bots and spiders. To see them, check your server or CDN logs.

User-triggered agents such as ChatGPT-User, Perplexity-User and Claude-User are the most useful here. A rise in their requests for a page suggests AI tools are reading it to answer questions, even when few people click through. Treat this as a visibility signal, not as visits.

What the published numbers say

Use dated, sourced figures, and treat each one as a snapshot of its own sample.

• Fewer clicks when an AI summary appears. In a July 22, 2025 analysis of browsing data from 900 U.S. adults in March 2025, Pew Research Center found that users who saw an AI summary on Google clicked a traditional result in 8% of visits, compared with 15% when no summary appeared. A link inside the AI summary was clicked in 1% of visits.
• Fast growth from AI tools. Adobe reported on January 7, 2026 that traffic to U.S. retail sites from generative AI tools rose 693.4% year over year during the November 1 to December 31, 2025 holiday season, based on Adobe Analytics data covering over 1 trillion visits to U.S. retail sites.
• Google's view on click quality. Google's AI features guide for site owners (last updated December 10, 2025) says that clicks from search results pages with AI Overviews are higher quality, meaning users are more likely to spend more time on the site.

None of these tells you how your own AI traffic converts. Your GA4 data, split by channel, is the only reliable answer for your site.

A monthly AI traffic report (hypothetical example)

For example, imagine a B2B software company that wants one AI view for its monthly marketing review. A practical setup:

1. GA4 Traffic acquisition, using the custom channel group, filtered to "AI assistants (all)": sessions, engagement rate, key events and revenue, with Session source as the breakdown.
2. Landing pages for AI sessions: the pages AI tools send people to, compared with the pages that rank in organic search.
3. Search Console generative AI performance report: AI impressions by page for the same month, next to Organic Search sessions for those pages in GA4.
4. Server log counts for ChatGPT-User, Perplexity-User and Claude-User requests on the top pages.
5. Direct traffic trend on pages that gain AI impressions or agent requests, as a rough sign of AI visits that lost their referrer.
6. UTM-tagged links you control, such as links in directory listings, press releases and partner pages, so those visits are never counted as Direct.

The company would review the regex each month, add any new AI hostnames that appear in Referral, and note the date of each change so trends stay comparable.

Build AI attribution into your reporting

INSIDEA is an Elite HubSpot Partner and the growth operating system for modern businesses. If you want AI assistants, AI Overviews and direct traffic reported clearly next to your other channels, our growth marketing team can help you set it up.